Air con changing the rubber seal to joint ahead of rear offside wheel

Assistance needed please. I have a leak from the joint ahead of the rear offside wheel. I had the rubber seal changed by a local garage last year but i still had a drip / leak. They then added an air con leak seal product which we were hopeful would sort it out. This didn't work either. I then got them to de pressurise the system so i ordered a new rubber O Ring and today i tried to change it. I managed to undo the bolt which was very tight. Then cleaned behind both ends of the air con pipe in order to slide back the Alloy pieces that clamp together. Looking at the photos, i then slid back the alloy bracket nearest the rear wheel to give clearance. On trying to move the alloy bracket at the front end all i could do was to semi rotate the alloy block / clamp. I could not slide it backwards. I need to do this in order to get to the O Ring. To get more play in the air con pipes i then removed the 6mm hex plastic screw for the brackets but couldn't release the plastic pipe support clamp. The other side was so tight that it's now mangled ! Please can someone advise on how i can slide back the the alloy clamp (unless a hammer is needed). I've already cleaned and lightly greased the pipe. Also any thoughts on how to remove the black plastic air con pipe supports.

On my 986 that bolt just came free at the point the inside of the Allen bolt head was about to chew itself up. Use a fresh bolt when reassembling. The main difference is that the hose towards the rear on the 986 is flexible as id runs up into the front of the engine bay. so can't help there I'm afraid, but it still uses the same clamp (Part number 999 511 230 40) which should hinge open if this picture helps:

Many thanks for the reply and yes it does help me. I now understand how it works. Might put a mole grip on the head of the plastic bolt and loosen it. I'll have a go tomorrow

good effort with this job so far. It certainly doesn't seem easy. I had an air con guy visit this morning to check for leaks in my system 996 C2. His leak detector said was coming from same place as yours but he has suggested replacing the pipe (99657309102) completely as it most likely has tiny holes. He said the pipes are covered in something and when water gets in there due to stone chips they corrode and leak. So I've ordered a pipe from Porsche directly in Guildford as it's cheaper than anywhere else. Will be attempting to tackle it on Wednesday afternoon. I'm very worried about the bolts shearing off as drilling out etc is going to take me ages and probably more tools than I currently own. I'll be applying plenty of WD40 over the next couple of days to the joints to hopefully ease them a bit. I've looked everywhere for a video of this process but couldn't find one. Perhaps I'll try and make one as I get stuck into it.

I had to use a mole grip to turn the plastic screw as the hex allen key mangled the head. Surprisingly the head still looks ok so i will grease the thread prior to replacing and reckon i can reuse the black plastic screw. Thanks again to A1/2cwt for his photo which really helped in knowing how to tackle the plastic screw. I got it off in minutes. Very easy when you know how clips work !. I then got enough slack in the long straight pipe that runs under the car to pull the joint / pipe apart. The leak was in the joint and on removing the O Ring, i found that the female side of the joint had crusty / dried air con fluid in the groove. I then carefully chipped it off and cleaned the groove hopefully without damaging the alloy. Looked everywhere for the replacement O Ring in the car / garage / as i know i have it somewhere but no such luck. So now ordered another one from Design911. Can't wait to get it all back again and then pressure tested / re gassed. Hopefully you get the bolts off. My HP pipe was a struggle but we failed to change the LP pipe as can be seen in the photo so i've left alone as its leak free - see photo above. A few photos to show the job starting with the photo of the leak. Hope this helps others in understanding how to attend to the joint

Use an aluminium based paste. It is a steel bolt into an alloy thread, it will chemically fuse over time, just like drip links and coffing arm bushes do too. Allen key just got mine off before the Allen hex burred out with a big adjustable spanner holding the bigger alloy block. It is also not unknown for the alloy pipes to get damaged due to their proximity to the jacking points.

Nice one. Thanks for the photos they'll definitely come in handy as I tackle this job. Bad luck on the o ring. Hopefully you'll have it sorted before the heat returns.

I collected the new air con pipe from Porsche this morning. Have the rear wheel off and the back jacked up. Annoying the rear connection on this pipe is right next to the jacking point so makes it very tough to get in there with the tools. I sprayed lots and lots of wd40 on to the joint but so far no luck in being able to undo it. As I'm turning the hex nut the entire aluminium joint is spinning too. I'm a little concerned that if I turn it too much it'll do some damage. How did you undo the hex bolt? Did you have to hold the joint in some way so as to get better purchase when turning it? Any help or advice would be great. Thanks

Hold the joint with a large adjustable spanner and try turning the hex. That didn’t work for me so the next option is to drill the bolt out (tricky) or cut through the aluminium joint BUT don’t damage the side of the joint on the pipe that goes over the engine! It’s an engine out job to replace that side of the pipe.

Thanks that worked a treat. It's just come loose. Now to have a go at the front

Keep going mate and all the best with the front. Keep us informed on how you go. I got my new O Ring today so will start putting it back together tomorrow. Just soaked the O Ring in air con fluid and will lightly oil the ends before putting back together as stated in the workshop manual. Tightening torque for the refrigerment line (M8 x 32) is 23Nm. Hope this helps

Thanks. All sorted now. Removing the old AC pipe out was a right faff. I managed to disconnect it under the car without too much fuss but found there was quite a bit to deal with under the driver's arch to make room to manoeuvre it out of the car. The stages were as follows : Jack up front drivers side Remove driver side wheel Remove complete arch liner with a really tricky push rivet right behind the spring (took ages getting that one out) Unscrew bracket holding the fuel filler tube Remove all lines from fuel filler tube and push it towards the spring as much as possible Remove large black plastic EVAP box (carbon box) from behind wing. Unclip one line from the bottom of the evap box. Now you gain access to remove clip holding the AC lines under wheel arch. Disconnect thinner AC line to allow thicker AC line to pass through it. Wiggle the thick AC line through the wing pushing on the fuel filler pipe to create enough space. Push the long length of the pipe under the car to allow it to thread downwards and out of the arch. I also replaced the dryer today including all new o ring seals and also seals on both condensers. Need to get the mobile AC guy back around later in the week to re gas and perform a new leak test. Fingers crossed that's the end of this saga.

Great work there. Think of the money you saved plus having the good experience. I change the O Ring on the high pressure line by the rear wheel last week. All ok but concerned that i could not get the 23KN torque as the ali bracket / clamp kept turning. I reckon the Porsche Specialists have a special tool cut out for the pear shape clamp to hold it in place when tightening up ? Took it to the garage to get a leak test and all ok. Got it refilled all for £114 which i was pleased about. Fingers crossed it all holds up.

Yeah they are really difficult to tighten. I just used the large spanner locked around it to prevent it from spinning as I tightened it up. I used I guy called Gary who's company is https://autoairconditioningltd.co.uk/ Absolutely brilliant service and has years of experience. Charged £90 for the leak test and complete re gas. Anyone in Surrey I would highly recommend him.

Hopefully it was 23Nm, not 2.3 tonnes!!! An adjustable spanner hols the pear-shaped sections well enough to get the torque.

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Good spot and correct - my mistake. I did try numerous adjustable spanners but not any real success. Will check underneath for leak in morning but the garage did a leak test and the joint was holding up. Fingers crossed.

I've also used large mole grips to hold those joints whilst you tighten the screw when I fit a new compressor.

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I think (and hope) I have a simliar problem to you. I have very small flourescent UV dye puddle just in front of my OS rear tyre when the car has been standing for a few days. I've felt the pipe all along the body and its smooth dry all the way to the plastic block that mounts them to the underbody and all around the plastic mount is also dry and smooth. Just a bit further to the rear above the splash guard the undertray has a light misting of UV dye 'around' the place and on the underside of the splash guard, as if its blown there by car motion and an aerosol type leak. It seemed to start just after I'd had a clutch, DMF and AOS and I know they had to drop the engine and move it a bit to get to an AOS bolt, so am hoping that the leak is at the joint where it may have flexed during that work and triggered a leak... will get the trays off and have a proper look when I get chance. I'll try just nipping up and spraying brake cleaner around to clean it up and see if it is still leaking, but at least I have hope its possibly a new O ring... hoping it's the joint and not the rear-most pipe!

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All the very best to you. If it's at the joint, spend time cleaning it up before reassembly. Mine has held up and no leaks.

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Good news! What did you use to clean up the flanges and inside the joint before refitting the new O rings, scotchbrite pad for the surface and scrunched up and run around the inside rim? (that's what I had in mind, but whatever you did clearly worked!) I am also thinking of sticking rubber bungs in the ends when they are separated and sanding down the underbody pipes for the 6" or so before the joint where there are some small lumps forming. Neither are leaking, but AI tells me sanding it back get rid of the black coating and patches of expanded oxidised aluminium beneath (which is the lumps) and back to bare metal, then etch priming, painting and after a week covering in lanoguard motogrease should extend the life of the pipe significantly... got to be worth a go whilst in there (and only on the body side, not the engine side!

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I stuffed some of my garage heavy duty blue roll into the pipes before i started and make sure you pull it all out - don't use toilet paper as it easily rips. I then used one of my modelling kit pointed ends which have various shapes with pointed ends (like what the dentist use) to removed the lumpy dried air con product. Then 400 / 800 paper. I only did around the ends as the inner pipe looked ok. I also sanded the alloy block faces for a smooth tight fit and fitted new allen bolts. Hope this helps. Rog

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Plus a new O ring fitted but make sure you lube it up with air con fluid. Put your finger into the pipe before you start and get some out and wipe it in cling film. Then leave the O ring in the cling film and lube it up. Rog

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Thanks, I'll see what I find! I have some assorted plastic picks and scrapers to pull out any lumps. Cheers.

I’ve a vague recollection that the o-ring is an odd size so it’s worth buying an expensive Porsche one to make sure that it fits perfectly. Maybe someone can confirm?

Just in case it helps anybody else, the Porsche OE parts I ordered are: 1x Cable Holder / Pipe Clamp: 999 511 230 40 1x Rubber Isolator Bush: 999 511 231 41 2x Air Conditioning Line O-Ring (Large, 17 x 2.0mm): 999 707 534 41 2x Radiator Air Conditioning O-Ring (Small, 10.6 x 2.0mm): 999 707 434 41 I got 2 of each O ring size (large for low-pressure line, smalll for high-pressure line) in case I fumble one, and guarantee the plastic pipe mount will break or the plastic screw will round out. I got another rubber mount insert as I know it will be clean and supple so should help protect the pipes in the known rot-spot. I plan to sand and paint the last 6" of the underbody AC pipes to get rid of any surface rot-in-progress so hopefully a clock-reset on that part of the system. OPC much cheaper than anywhere else, all came to less than £30 inc VAT. Also got some new bolts for the pipe union as they may chew when removed or have corroded threads. Porsche combination bolts were over £30 for 2, so I got some zinc plated 12.9 grade M8 x 30mm allen head cap screws at 5 for £3.99 off eBay and have some M8 washers lying around.

A tale of joy and sadness so far and I need some sage advice please! The starting point - puddle on garage floor just in front of the OS rear wheel. Cleaned up and found the smoking gun, both are actually leaking, the fat one more obvious but tiny bubbles in the crack between the union flanges on the thin one too. My bits arrived from Porsche, so after soaking both aluminium unions in PB blaster yesterday a couple of times and again this morning The joy- I managed to get the bolt out for the wider low pressure line and separate the union. The perished green O ring fell out and it had split! There was the smoking gun so a little cleanup and re-assembmy would see me right, very happy, so I wedged a tapered silicon bung in the end of each exposed pipe and went on to disconnect the thin high pressure line... I was ever so hopeful, it felt like the bolt was just about to come out, I felt it move slightly, so would it a tiny angle tight again, then back the other way, but it snapped. It had clearly already decided it was going to snap before I even approached it. That is my story and I am sticking to it. I've wrapped the union in cotton wood pads, soaked them in PB blaster and wrapped kitchen foil arounnd to hold the PB blaster-soaked cotton wool against it all overnight to hopefully encourage separation. My plan/thought is to try and separate the flanges as the bolt head is missing, the unthreaded side of the flange should separate, and I can see there should be 5/6mm of snapped bolt protruding from the other side for me to try and remove. Planning on another PB blaster soak, then heat the flange gently with a heat gun rather than gas torch, and see if I can use mole grips to persuede it out... I have some questions though please; 1, General help, has anyone been here and done it before? 2, Do either or both of the flanges (thick flange on underbody line side, or thin flange on 'do not damage this pipe it goes to the compressor' side) slide backwards along their respective pipes, or are they both fixed to the mating ends of each pipe and neither rotate nor slide back along the pipe. 3, If my plan is along the right lines, what can I try to separate the flanges? I think I should not, say, tap a chisel at the joint crack or try any wedging/prising as it could damage the union, certainly on the wider side of the 'egg' shaped flanges, but what about simliar on the thinner 'bolt' side of the egg shaped flange? It feels like gettng a chisel just to slighly open the gap would allow me to get the edge of a sharp plastic trim tool in there to tap in and twist to separate the pipes and show me how much bolt I have left to try and grab. Any help appreciated, thanks!

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Which bif of the ali flange slides back along the pipe, is it the thinner unthreaded part on the 'engine side' pipe, or the thicker, threaded flange on the underbody pipe? I've got a challenge and want to make sure I am not manhandling the wrong bit, these pipes are soft as I am sure you know, so not many chances to make mistakes before it gets spendy! Cheers.

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From memory only one flange slid away. Looking at a photo it looks like the flange (wheel side) slid back on the larger pipe. I didn't do anything to the smaller pipe. Apologies for the delay in writing but only just clocked onto the site and hope this helps.

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Thanks, on my larger low pressure line that I managed to disconnect, I have just got the thinner male side to rotate on the pipe, so that matches what your pictures show. It doesnt slide back yet but as it moves I am sure it could be loosedened up if needed. The other thinner high pressure pipe where the bolt sheared beat me... 10hrs yesterday and could not separate the flanges! Heat, deep creep, PB blaster, cleaning out visible gunk in the hole and protruding threads the other side, blades, chisels, hitting... Just about broke the seal on the O ring side with a little 'pffft' noise, but the bolt side of the flange, despite being unthreaded, is just not moving!! Anyone got any ideas or techniques I can try? Reluctant to try and drill it myself so may have to admit failure on this one...

Not easy. Not being able to twist it free is the issue. You're trying to slide the narrower section/flange away from the thicker section..correct? but the broken bolt is still threaded into the thick section/flange and you can't twist it because the bolt is preventing that.? You could try pressing something very thin like a Stanley knife blade between the two surfaces using something like a small G clamp just enough to get some fluid in there. I don't know, it's a tough one that, have you tried warming it up carefully? probably with a heat gun rather than Mapgas torch.

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Indeed, I had planned to disconnect, clean up and replce O rings, refurb the final 6" of pipe before the join that started to buble, swap in my new black NRF condensers while the system was empty, and then stick the new receiver/dryer in just before my regas appointment... sadly I fell at the first hurdle! Yes you are correct, I want to separate them, so pushing the thinner flange away is the plan, as the hole in that is not threaded, so if I can get it separated and lift it over the snapped bolt, there shoudl be a decent 5-6mm of protruding bolt to get to and try to remove it. Problem I think is the bolt remnant, is still acting as a locating pin preventing twisting movement, and although it's not threaded in the thinner flange, it's clearly gunked up with expanded aluminium oxide. I tried heat gun, varous penetrants, soaking cotton wool in PB blaster, wrapping rounf the joint and holding it in place with a big ball of tinfoil overnight, tapping a blade in a scraper into the gap to try and widen it a little to get prising room, a chisel, even put an inflatable bag under the chisel and inflated it to push the chisel hard into the gap, then heating, then penetrant and hitting the chisel near the top to try and force the flange to break its seal.... 10hrs over the weekend. Damn you galvanic corrosion! Feeling beaten so I fear I may have to hit this one with my wallet... hopefully on a lift with better visiblity and accessability it may be possible to brace it and try to drill out the bolt or get an extractor in there with an induction heater on the flange or something.... Be a sod to drill too with the pipe being there!

Be very careful with heat, you don't want to heat up any residual PAG oil , it turns into nasty stuff. 2 vice grips with opposing force might break the crusty bond in the flange and surrounding the bolt, have you tapped it a small ball peen hammer? I'd be trying to free up the bond before trying to seperate. When I say tap I mean many many times all over, sharp hard taps. Not easy at all especially if you're not up on a lift. My Turbo ones are leaking and I went to undo the bolt thinking the system was empty. I used my 1/4" impact gun set on very low for several minutes and eventually it span out very fast and sprayed green PAG oil everywhere, it wasn't empty at all. I quickly screwed it back in and that stopped it but I need it sucked out to go forward with the other bolt.

Last thing I would do is try any sort of twisting as you may damage the pipe and aperture it goes in. Just has a chat with the lads next door to me about what options you have. Your best course of action to break the seal between steel bolt and the aluminium is thermal shock. Heating it up takes to long for it to have a decent effect, it's cooling it quickly that gives you more of a chance. So you need to get your heat gun on it and then get some way of dowsing it with water to cool it instantly (and shock it). Whilst repeating this procedure, keep tapping it with something hard (like a hammer and not a mallet). Eventually you may start to beak it down and it free it up. Ditch putting the WD-40 on whilst you are doing any of this. The other option is to get a hack saw and saw from the outside a slot right on the joint until the saw blade hits the bolt (or at least a deep enough slot to get a decent flat head screwdriver in). Once you get a screwdriver in, start twisting back and forth - might want to get some mole grips or an adjustable on the handle if it has flats on it. The two parts will still clamp together ok afterwards even though you've cut a slot in the outer profile. Good luck!

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Yes I stayed away from the torch and stuck to a focused nozzle on a heat gun pointed at the block. I thought mine was empty, but still wrapped a towel around the joint when I released the first one and it's a good job I did. Learned my lesson a while back when removing a dead condensor, got it right in the face. Thanks both. Maybe some freeze spray designed for electrical components from RS would help with the heat-shock cycle. I had considered creating some leverage in the actual aluminium flange on the bolt side of the 'egg' not the pipe connector side. I shyed away as the thin flange with male pipe is on the engine-side and I've heard scary stories about damaging/replacing those, although a thin hacksaw slot right on the tip of the thin end behind the bolt could alleviate pressure, allow some penetrant to access the bolt shaft directly and also give some prising space. As you suggest, trying to rotate a flatblade in there is trying to separate at exactly the right point. Hmm... need some brave pills to try that one though!

Yes, cut a slot in here: And then wiggle with a screwdriver. I have some hexagonal drivers (as seen in photo) so you can get a spanner on to rotate:

It does look like a technically plausible idea thank you Alex, I'd have to get the car back up on stands and see what kind of access angles I can get it's a tricky area to work on especially when its loosely anchored aluminium pipes that cant easily be manipulated. I've removed the rubber/plastic mounting blocks and wedged a block of wood with a towel above it between underbody and pipe to try and 'present' the flange better and allow shap hits with a drift to communicate with the metal better instead of just twanging the pipe around and absorbing the sharpness of the blow... I will think what to do next but as always appreciate your help!

I've slit a ziplock bag and encased the flanges, and ziptied around the top, filled with plusgas totally submerging the assembly. Hopefully over 2-3 full days it will creep along the bolt via protruding end, snapped end and tiny gap betweek the flanges and just pop off at the weekend! If not, I have bought a small bottle jack to brace my 4lb BFH head behind the flange to use as an anvil, and a 2lb BFH and an assortment of brass drifts to hopefully persude the corrosion to give up... can't let it win!

Well that was a bit of a saga! After soaking for a week in a little pink plusgas bath, the flanges separated with a few sharp taps with a brass drift on the section of broken bolt through the counter bore, and a good general clout with a hammer on the side. With the male flange off, the exposed broken bolt shaft was seriously packed with aluminium oxide, not hard to understand why the bolt wanted to stay where it was forever! Tried the heat, cool, lube, hit, cycle a few times and got a heavy duty stud remove locked on, and a heavy adjustable spanner to counter hold the flange, and started to try and persude it out... it was moving maybe 1/32 of a rotation, then repeat cycle and try again.... managed to unscrew about one thread and it snapped again, flush. Went on to D911, got price for new high pressure line and resigned myself to buying a new one. Then as my pipe was now mentally sacrificed I attacked the bolt with a left hand drill bit, holding the flange freehand... the drill went straight through no bother, tried an extractor but that was having none of it so just stepped up the drill size using normal bits until I had an 8mm hole (tiny bit wonky but not too bad), and the remnants of thread came out. 10mm wire brush in the hole cleaned it up nicely and managed to get 2 fresh OE O rings fitted and just bolted through with a 40mm bolt and a washer/nut on the end (and some ceramic paste on the threads. Both condensers swapped for black NRF ones with new O rings, and a new NRF dryer went on yesterday... off for a regas this afternoon, fingers crossed it holds vacuum, boils off any moisture and fills nicely with no leaks! UPDATE - So far so good. Held vacuum for 30mins and recharged no issues, icy cold. Will check the joints with UV torch again in a few days but looks like I may have saved it!