Ugh..gelled brake fluid. Now what?

Apologies in advance for the long post but over the last couple of years I haven't really driven my car much at all aside from the occasional trip to grab something to eat and I was recently given a pressure brake bleeder kit, so with the best of intentions I decided to try it out over the holidays. Unfortunately when I took the cap off the brake fluid reservoir and wrestled the filter cup out, the top of the brake fluid had the colour and consistency of honey. (me: ...yeah thats not good) I stuck a syringe in there to see if I could suction it out and it really didnt flow at all , however underneath the top 3-4mm "gel layer" the fluid was very liquid but as I would vacuum it out the 'honey' just coated everything as it went down (fluid level sensor, etc.) and I decided not to let it get down to the level of the master cylinder and through the rest of the system. So I refilled it for the time being and ordered a new reservoir and master cylinder just in case. Out of curiousity I also wanted to see if the addition of new fluid would thin/dilute the gel layer but it didnt seem to do much, although also hard to tell. After getting the new reservoir and master cylinder I then lined the frunk with thick plastic, taped it up well and just popped off the old reservoir at about 3/4 full of fluid. Upon inspection with the reservoir removed, the fluid on top of the two master cylinder inlet ports was still liquid and I have not pushed the brake pedal since discovering any of this at the beginning of December (not wanting to make a bad situation worse). So I installed the brand new reservoir, topped it off and tried the pressure bleeder starting on the passenger rear, inboard brake. It flowed about 25ml of brake fluid out before stopping, and this was at about 25psi on the pressure bleeder. I noticed that the fluid coming out of the bleed valve had that same honey-like consistency. So...obviously this is a mess on the inside in various places, the gel is definitely soluble in brake cleaner but I'm just not sure how to go about purging/cleaning the whole system completely without damaging it further. I'm considering the following course of action so tell me if this is really off-base: -fully remove bleed valves and just pump out fluid with old master cylinder until it flows freely -remove and spray brake cleaner inside all the inner-to-outer caliper "u" tubes -detach output lines from ABS module and spray 'back' from the module to the brake connection through lines with brake cleaner -detach master cylinder to ABS input lines and clean with brake cleaner -replace master cylinder Biggest question is how do I even clean the ABS module? is it as simple as spraying brake cleaner/denatured alcohol in there or is that gonna screw something up? This is a 99 coupe with ABS only. I hate dealing with brakes but this looks like it's gonna get very expensive very quickly if I don't do it myself so any and all advice is appreciated.

With the bleed valve open can you push anything out with pushing down the brake pedal? I would try the inboard on the left rear and see if you can get it flow clear.

Aside from what other's will tell you about how to best get all the old stuff out, don't forget your clutch line and slave as they use the same resevoir and are often overlooked even when clutches are replaced. If it was me I'd run new fluid through as you are doing, then, if the brakes are working as they should, repeat after a couple thousand miles.

hbdunn Oh, thank you that's a very good point! I didn't try that but definitely makes sense and I'll give that a shot before further disassembly. Makes sense that it's flushing the main line but cant pass through the tiny bleeder hole. Unfortunately will have to wait another 2 wks as I foolishly timed this to be right before a business trip.....dang now I have a ray of hope again!

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Lol, yeah definite "scope creep" on this project I know! I'm not sure I even looked at how to bleed the clutch but will examine it after I get the brake situation sorted a bit better. And yeah, once I get this partially resolved I'll certainly switch the fluid out again in a few months.

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To elaborate on @DSC800 , I wouldn't call this scope creep. The clutch cylinder uses brake fluid from the same reservoir as the brakes. There is a slight divider at the bottom of the reservoir for the two systems. So, if your brake lines are gelled, then your clutch hydraulics likely are as well. Bleeding the clutch is very similar to the brakes. The clutch cylinder is on the top driver's side of the transmission, and there is a bleeder valve, exactly like the brakes, on top of the cylinder. It's a bit of a pain to reach, but not too bad. I would definitely put a small hose on the bleeder valve, like what I imagine you're doing on the brakes, other wise the fluid will drain down the clutch and all over the transmission. With a pressure bleeder, you should be able to do it just like the brakes. Pressurize the reservoir and open the clutch valve to release the air or dark fluid. You could also do it the old fashioned way with a partner to open/close the valve and pump the clutch if needed (like pumping the brakes). Good luck!

Wow� that�s bizarre! I wonder if it�s from mixing two different types of brakes fluid (ie dot 4/dot 5 etc). Surprising it�s not darker colored as that�s what normally happens as fluid get old and heat cycled�

I think I have an ABS Pump out of a 99 that I could let go cheap if you need it. PM me if interested.

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Thanks Kris, appreciate the offer and I'll let you know once I get back home and see how bad it is.

Okay just a quick update: my kid and I worked together today to bleed the brakes the old-fashioned way and this seems to have been successful in purging the thicker gelled fluid rom the lines. Each brake definitely had some thicker gel come out of it throughout the bleeding and oddly enough the left front seemed to be by far the worst. It popped the drain line off a couple of times due to the poor flow/high pressure of the gelled fluid during the bleeding...making a complete mess of everything of course. But overall this gets me back on the road and I'll flush it again in a month or two and see if anything else comes out. After talking with another owner, I probably also need to change out some of the other things that have likely aged poorly like the flex lines. I'm just glad I was able to purge most of the gunk out without a complete teardown for now. Sincere thanks for the advice to just go back to the "old ways" and just purge it with a helper stomping on the pedal! It worked.

K996, Did you find out the cause of jelling? I, for one, would be very interested in learning so I won't experience your unfortunate case. Bahman

Makes sense to change your brake fluid every so often. Porsche indies are tied into the PCA tech inspection sheet for DE which asks for fresh brake fluid not to mention you want fresh engine oil. What this means is if you call up a Porsche Indy and ask them what it costs for a PCA tech inspection and what's included, you may find for $300 give or take you can get and oil change and brake flush, not to mention a quick PPI look over.