Brake fluid warning check your asap

[chris52]

I am doing some work on the car and as a result needed to disconnect some brake lines. When I came to bleed them (I use a self bleeder that puts 20psi in the system) I couldn't get any fluid out then this thick clear jelly like substance started oozing out of the bleed nipple then just stopped again. The reservoir was also full of this jelly. The jelly was in all the brake lines and had blocked the rear brakes completely at the compensator, so I have been driving on front brakes only for some time even with the brake pipes removed at the rear and my foot pressing as hard as I could on the pedal not a drop of fluid reached the rear calipers, very scary indeed.
I only got the car in July last year but looking through the history it was last changed in 2014 and about 4000 miles ago at a well respected TVR specialist. I have now read online a few other people having this issue mainly on bikes and the general consensus is that it's water getting into the fluid not mixing types of fluid.
So just a word of warning check your fluid and if in doubt change it. I was lucky that I found it when I did I had already lost rear brakes with the amount of jelly in the system it wouldn't have been long before I lost fronts as well.
Now this may be me being synical but I wonder if the fluid was actually changed in 2014 and if it was what fluid did they use? Or was it just a bad batch of fluid or perhaps some old stuff that had been hanging around the workshop for a while unsealed.
Chris

[RobXjcoupe]

Dot 3/4 is glycol based, 4 being the better. DOT 5 fluid is silicone based, and shouldn't be mixed with a glycol based fluid, they react against each other.

Dot 5.1 fluid, however is glycol based , and basically has the wear/contamination properties of the silicone DOT5, but can be mixed.

I reckon someone put dot 5 in by mistake or the system was filled with dot 5 and hasn't been changed every 6 months.
It's serious, your master cylinder needs to be removed to check the rubber seals as well as those around the caliper pistons.

[chris52]

I posted this on on the facebook site as well and mixing dot 4 and dot 5 is what has been suggested. I'm not sure this is the case but it certainly could be. Dot 5 is purple or violet in colour and costs about 5 times more that dot 4. There is nothing in the history file about this. There was also no purple or violet colour in the fluid. I have never seen this before and have worked in the Motor trade for 30 years. Maybe your right I don't know but it's worth checking just to be safe.
I have flushed the whole system now and it seems to be ok all seals seem to be holding up well. But I will keep an eye on it and if needed will get all the seals replaced.
Chris

[TVR Beaver]

What I find strange is the fronts were okay?.... why would it only do it on the back?... if its a reaction due to mixing would it not do it everywhere?...

[chris52]

The fronts wer the same full of this jelly but they were still working. Whatever it was seems to dissolve in new clean brake fluid and turn back to liquid to sieved the brake fluid from that came out and I had pile of this jelly left in the sieve but as I poured the fluid I used to flush the system it disappeared. Very strange indeed I think I will see how it goes but do another full flush in a few weeks just to be on the safe side.
Chris

[RobXjcoupe]

all I can think of is a previous owner may have thought upgrade the brake fluid for a track day with dot 5.1. Then the car changes hands with a note dot 5 brake fluid has been used. Who ever didn't realise there is a difference between dot 5 and dot 5.1 and a mix has occurred.
Dot 5 is a race type fluid for high temperature applications and I think in a brake system with no rubber parts.
Dot 5 needs changing every 6 months because is turns jelly after about 12 months. I think mixing the two fluids speeds up the chemical reaction.
Dot 5.1 is I believe just as good as dot 5 but can be used to upgrade a dot 4 fluid with no side effects on rubber components and no jelling up after 6-12 months.
Any hows. At least you found and sorted the problem 👍🏻

[Lilmsknowsnthnboutcars]

Hi Everyone. Just wanted to say thanks for the info. Been having problems with my abs system& traction control on my 2003 saturn l300 since the bearings were replaced. The brake pressure was never the same after that. Last week my brakes went out as i was driving. Fortunately i didnt wreck. Brake went to the floor with barely any braking left. As we bled the brakes again last night this jelly substance came out. We had no idea what it was. We've been scratching our heads not knowong whats wrong. Brakes are good, could this explain why theres been no fluid loss? Is it possible the brake lines need to be replaced completely? As my username states i know nothing about cars so appreciate all the advice!

[mk1fan]

DoT 3, 4 and 5.1 are (simply speaking) chemically the same. These three can be safely mixed with no reaction. That is, you can top up a system with any of these fluids in it with any of the the three.

DoT 5 is entirely different chemically. There is a reaction if you mix it with any of the previous three.

[mk1fan]

You need to flush the system through with fresh (appropriate) fluid to clean it out.

[FFMan]

surely an mot would pick up the loss of braking