I have a 1995 Hijet 660 S110P with front disc brakes. Both front brakes locked up unexpectedly! The pedal is solid with no movement. When I opened a bleeder valve on a brake caliber, the pressure was released and the front tires were freed. I drove it a few miles and it did it again. I think the master cylinder needs to be replaced. Please let me know what you guys think and if anyone has experience or a video on how to replace master cylinder. Thanks Jeff
There is typically a residual pressure valve in the master cylinder with disc brakes which prevents the calipers from retracting too far. It can get clogged up. When was the last time you did a complete bleed to exchange all of the brake fluid? I’d try a complete bell with new fluid, before i ordered a new master cylinder. The brake fluid will probably be less than the shipping on the brake cylinder.
I recently bought the truck with only 32500km. Brake fluid could be the original. I will do a complete bleed with new fluid first. Thx for the info.
not a Hijet, but from experience with my 1988 BMW E32 750 I know that the brake master cylinder get's stuck, the brake master is made by ATE and has 4 seals and a bakelite ring. Seals p/n 2 x 03.3302-0017.1E, 1 x 3.3402-2508.1E, 1 x 3.3301-2537.1E, then there is a bakelite material ring inside,. The bakelite ring when older also can start to getting stuck on the shaft. The bakelite ring ( pressed , or caused by age very tight ) has to be removed and the inside hole has to be smoothened by a reamer or with 400 wet grit sandpaper until the ring moves freely on the shaft again. disassembled the brake master cylinder and slightly polished the bakelite ring down and replaced the seals inside. Pic http://www.bimmerboard.com/members/shogun/BrakeMasterM70.jpg check if there are brake master and brake caliper repair kits for your model, Yokohama Motors has quite a lot of repair kits for brakes for various models, including brake caliper pistons https://yokohamamotors.net/page9.html piston problems, also an example of my BMW model , check the dust covers of the pistons http://bmwe32.masscom.net/sean750/caliper/RebuildBrakeCaliper.htm
