Brake fluid turned to Jelly

The brake fluid in 93 Chevy pickup turned to jelly, swelled all rubber in system and locked up brakes. Nothing done to it since January. When fluid cooled it seemed to separate. Any ideas why?

When was the last time you replaced the brake fluid?

Don’t believe I ever did.

Start by replacing the 15 year old fluid and bleeding the system completely to get rid of all the old stuff. If you are lucky, the system will be OK with the new fluid.

Thanks but I may have waited too long. All the rubber had swelled and the mechanic I went to said I must have had some incompatible fluid introduced. He didn’t mention the possibility that it could just be old. I had front brakes repaired about 5 years ago and the system bled and added to. I know nothing has been added since then.

I would guess that your mechanic is correct about the wrong fluid being used. It is the first thing that came to my mind also. You are in for a total brake system repair job it sounds to me.

If that’s the case, you are probably looking at replacing some brake components. I wouldn’t mess around with brakes, do whatever it takes to get them correct.

I’m curious about this. How do you mean it “turned to jelly”? Did it come out really thick?

It sounds to me like the brake fluid might have boiled, due to very old brake fluid or water contamination. This pickup doesn’t take an exotic kind of brake fluid or anything, so I would find it unlikely that incompatible brake fluid would have been introduced, unless someone added something that wasn’t brake fluid at all by accident.

It is almost certain that the fluid was contaminated with some petroleum product. Oil, power steering fluid, transmission fluid, etc., was very likely mistakenly added to the brake system. Rubber in the brake system is not compatible with oils and the rubber swells and emulsifies, ruining all rubber in the system. The calipers, wheel cylinders, master cylinder and hoses must all be replaced to ensure that the truck is safe.