Motor Mounts - Easiest DIY gone horribly wrong

Hey everyone, I've only had my Porsche a few months, and have done a few simple jobs on it (brakes, 997 shifter) which have been fun and satisfying. Thought I'd take a stab at doing the motor mounts because it looked easy and everyone loved the results. Used GeorgeCo's instructions which were great. Had a bit of trouble getting the car high enough to fit my jack stands under the rear jack points, trick was to use floor jack at point behind engine and Porsche jack at front jack point, then could slide jack stand under rear jack point. Finally got it jacked up and started pulling items out, got the right motor mount out no problem and dropped in the new one. While torquing down the top bolts to 25 ft-lbs, one of them broke leaving half of it still in the hole. After looking under the car I realized I missed the hole on the engine flange with big bolt, cocking the mount which I think caused the break. This frustrated me, but I figured I may still be able to drive the car carefully to the dealership to have them pull the broken bolt out. Then I moved on to the left motor mount, put in the new one, and while trying to tighten the back bolt, either my wrench or the moving the secondary air box hit a coolant line in the middle of the bay and it snapped off squirting coolant everywhere. I felt like I barely touched it, the plastic inside the tube is very brittle, I guess due to age. Questions: 1. Should I attempt to tap and pull the broken bolt out myself? Never done anything like that and a bit worried I might make it worse. If so, happen to know the part number for a new bolt? 2. Know the part no. for the plastic coolant line connector in the photo? Looks like I just undo one bolt and may be an easy fix to pop in a new connector (if I don't have to remove any belts to get to it) 3. Is it OK to start the car to move it? It has one broken motor mount bolt and a broken coolant line. Right now its blocking my other car (poor planning) 4. Will I have to flush the coolant now that I have air in the system? I'm debating whether I should try to fix myself or just have it towed to the dealer to have it fixed. Thanks for your help! Chris 2002 Porsche 911 Targa, 80k miles

Don't feel bad hat coolant connector can snap very easily. You need to plug the end or else coolant will be pumped out when you restart the engine. I replaced mine with a brass one from Home Depot. It will last forever. Does any of the broken bolt sticking out? You should be ok driving it to a shop bug the coolant coupler will first need to be replaced.

Don't feel bad hat coolant connector can snap very easily. You need to plug the end or else coolant will be pumped out when you restart the engine. I replaced mine with a brass one from Home Depot. It will last forever. Does any of the broken bolt sticking out? You should be ok driving it to a shop bug the coolant coupler will first need to be replaced.

Thanks, makes me feel like I'm not a total dumbass... Happen to know the part number from Home Depot or the size of the coolant hose? Is it ok that there will be some air in the coolant system? Will it work its way out? Thanks! Chris

Porsche part # for bolt - 90037805509 (old #), 90037805501 (new #). It's 8x40. I broke the same coolant fitting. Very common to break as they become brittle. Porsche dealers have these in stock. If memory serves me correctly, the part # is stamped on the plastic fitting itself. Pull off the whole fitting and check for the #.

Found some part numbers: 13mm bolt for motor mount - 900 378 055 09 - hexagon-head bolt (replaced by G90037805501, $9) Coolant system connector - A 996 106 226 51, or 996 106 226 52 - joining socket ($6)

Krazy K could have done that for you with a matchstick and a pair of tweezers.

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3/8 brass. Have a look at my repair page, scroll down and you'll see the picture. https://rennlist.com/forums/rennlist...-these-15.html .

You'll have to remove the remaining bolts and motor mount to get to the broken bolt, but it looks like access is pretty decent. Very good chance it will come out easily, often with just a left-hand drill bit. If not a screw extractor (which needs the bolt drilled anyway) will usually get it out. Also try and use a center-punch on the bolt before drilling to keep the bit centered properly on the bolt.

Great recommendation on the 3/8" brass coupler and drilling out the original mount. Got the coolant line fixed, tomorrow we'll see if I can get that broken bolt out. Picked up some M8-1.25x40mm Class 10.9 hex head cap screws at the auto store, anyone know if that's an acceptable replacement for the stock bolt? I believe its stainless steel, said it's for high tension use such as engine, suspension, etc. Stock part: "Porsche part # for bolt - 90037805509 (old #), 90037805501 (new #). It's 8x40." Thanks, Chris

CJ, You will see two things you need in this photo of my spare parts stash. The bolts in pic are Porsche bolts, not off the shelf. If your not in a terrible hurry, I can drop in mail monday.

Thanks KrazyK, but I've already got the parts on order.

BTW, throttle response seems much better, and engine seems to run much smoother with the new motor mounts.

Victory! Felt soooo good to see that bolt coming out, this weekend has been a roller coaster of emotions...

nice!

Nice! Glad it worked out... In general, be very careful with torque wrenches, especially with lower torque fasteners! Home mechanics often use them 'to do the job right', but at least several times a year, I hear about a friend or friend of friend who really screwed things up after busting stuff when using a torque wrench. It most often happens when using a medium or large size clicker-type torque wrench on a relatively low torque fastener... 25 ft/lbs isn't much... but if you were tightening it with a standard hand ratchet that is 8" or so, you'll feel still have pretty good feel for how tight it is getting, and it takes some work to snap a bolt. Slap on a 16" long torque wrench, and feel for a bolt with low torque is completely gone... If the wrench isn't set right, or broken, or you don't hear the click, or the bolt is lubed when the torque setting is for dry, or whatever, SNAP! Lastly, using the very low end of a torque wrenches settings are the most inaccurate, particularly if the wrench hasn't been stored properly. If you really want to tighten low-torque bolts (25 lbs and under) with a torque wrench, get yourself a specialty wrench designed for that purpose, or just skip the torque wrench completely and do it by feel!

Great job, glad you were able to get it sorted out on your own, job well done!!!

That's exactly what happened to me, these bolts called for 25 ft-lbs and that's the lowest my large clicker torque wrench goes. Definitely need to be careful!

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Yup. I'd rather see somebody use an extremely inexpensive torque wrench with the right torque range than a great torque wrench at the very bottom of the settings... A cheapie beam-type torque wrench is fine for those kind of low torque fasteners if you don't want to invest in something better with a low torque range. They are clumsy to read, which means users go really slow and sneak up to the torque reading instead of just pulling on it waiting for the click (or snap). I personally like the old-school dial type torque wrenches for low torque fasteners...

Glad this ended well for you Chris! Hope it does not discourage you from future projects - great pictures and updates by the way. Mark/Pelican Parts

+1 broken same connector

Over time you will develop a feel for what is tight enough for a bolt. Now days I only use a torque wrench for head bolts and that's about it. The rest I do by feel but not to the point that the bolt gets soft. Hard to explain but after a while, you can look at the size of a bolt and know how much is enough.

Amazing. I almost posted the exact same thing. I only use a torque wrench on critical fasteners. If you have had that sick feeling as you overtighten a bolt into aluminum then feel the threads pull, or feel a bolt slowly twist in half, you never forget it. If you simply must use a torque wrench for everything, get an inch pound one too. Also never use the "click type" torque wrench for small fasteners.

Not sure where I got it but I believe the torque value for that bolt is 20 ft-lb, not 25. That's what I used when I changed mine. Might explain why you broke it. Congrats on your recovery nonetheless. Martin

Just torque them down till they strip/snap and then back 'em out 1/4 turn. It's a feel thing.

Amazing. I almost posted exactly the same thing. Sometimes I use a little Elmer's white glue to glue the heads back on sheared-off bolts so the next owner doesn't notice.

So glad everything turned out OK!

Great job and glad you got everything worked out

+1 I broke that same stupid connector lastnight. Home Depot to the rescue with a more permanent fix.

I thought engine mounts was a very easy DIY. Oh yeh Right. It is if things go according to plan which they never do most times. lol

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Hurdi, with your level of patience you should be fine. I put my car on double 2X12's at all four corners, used the rear jacking point to raise the entire side of the car. Removed the air box, then made sure I could break the bottom nuts loose, then the top bolts on the right side, then moved the air injection pump out of the way, broke the top bolts loose on the left side. Had I not been able to break any of the fasteners loose I simply would have stopped and then been willing to pay to have the mounts replaced. My car has seen at least six winters, I don't live far from you. I was concerned that the road salt might have caused a problem, but everything came apart just fine. Might have helped that I take the car through an automated wash with undercarriage spray once per week in the winter. I also made sure that I had the engine supported with my floor jack, to the point where the load was off of the mounts. I use a hockey puck on top of the jack. I used a 3/8" drive torque wrench for the top bolts and 1/2" drive torque wrench on the bottom nuts.

Yeah, I just did mine and 99% of the effort was breaking loose the bottom nuts. Once that was done it was a piece of cake.

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Black pipe is your friend. I always have one as I no longer wish to struggle in my older years.

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I am confused as to the amount of jacking points to be used in the DIY job. I have at my disposal two racing adjustable jack stands and a low profile racing trolley jack. Now does the car have to be level on 4 jacks and then the trolley jack is used to take the engine weight say an inch or so? When you say 2x12s at all four corners, can you explain what you mean more fully please. I can borrow two more jack stands for the front if required from a mate of mine if the car has to be level. So would it be OK to use the trolley on the front to raise the whole side and put jacks in one side back and front? Same on the other side bringing the car up about 18 inch from the floor all around, then use the trolley to take the engine that bit higher to lift and ease pressure from the engine mountings? Or can it be done using my own two jack stands on the rear then go on slightly with the trolley to take the pressure from the engine mounts. Hope you understand those rambling questions.

OK I just ordered (or my wife did for me) 2 engine mounts plus an air filter from Pelican Parts $206. I also needed a coil mounting screw $1-75 and even though the air filter and engine mounts qualified for free shipping, the coil mounting screw DID NOT and Pelican parts were adding on $13 for a 1-75 screw. I told them to stick the screw where the monkey sticks his nuts. UP THEIR ***. That has pissed me off. UNLESS PELICAN PARTS READS THIS AND STICKS A COIL MOUNTING SCREW IN THERE FOR FREE.

I put the rear of the car on jack stands and supported the weight of the engine with my floor jack while replacing the mounts.

I did the same. Only two jack stands one on either side in the rear. I put a piece of wood between the jack and the bottom of the engine when I supported the engine with the jack so as not to harm it.

Glad to hear that you were able to get this fixed yourself...with a great bunch on this forum here to support you!

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Hurdi - I have run into the same shipping cost issue from a few vendors. The solution was to buy the low cost parts from my dealer, in some cases the parts are actually cheaper and you can have them in hand.

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You could simply use jack stands at the rear jacking points. I used double 2X12's because I happened to have a bunch of cut offs laying around and the car didn't need to be more than a few inches off the ground. You don't need to do it at all four corners, I did that because I was doing an oil change at the same time and wanted the car level. I also didn't want the car on stands as I was unsure of just how much force it would take to break the bottom nuts loose, I was after stability. Hope this helps clarify things a bit.

Congrats on your resolution. I hate that oh **** feeling when Murphy's law pops up and you start second guessing your decision. Not to be to incensitive but look at what you've learned!!!

I recently had my motor mounts replaced and really didn't see that much of a difference in shifting/permance. I did notice the tips were better positioned but I believe that to be due to the Indy replacing the exhaust for FisterD at the same time and adjusting the tips. Perhaps my mounts weren't as bad as I thought but the tips hung really low - see Avatar of before. (Car has 59,000 miles on it and it's an '02 C4).

OK I have everything ready for the motor mounts arriving in a couple of days. I Used PB Blaster to break the hold on the bottom nuts using a large torsion bar and half inch long reach wrench with extension. Then I removed the air pump no problem or enough to crack open last bolt. Then cracked open the other 3 bolts which hold the top of the mounts. Then took the strain off the engine letting the car rest on two rear stands. So the only thinbgs I am waiting for now are the engine mounts coming from Pelican Parts along with an air filter. OMG is it dirty in that engine compartment.

I didn't use any jack stands when I did my mounts. Just backed the car out of the garage enough for the rear to hang over the threashold. Slid the jack under the motor, and it was a matter of undoing and re-doing the nuts and bolts.