1985 Mondial Brake pedal not returning!

Slave cylinder might be bad. Does the brake warning light not go off?
Check for a puddle of brake fluid under engine.
The clutch is hydraulic and shares the same fluid as the brake system.
The slave cylinder is the most common part to fail.

 

ABS or not ? Has brake reservoir enough brake fluid ? if yes, and there isnt a leak at the brakes calipers, the seals inside brake pump are shot. There can be a leak between pump and booster (inside) also.

Guido

 

Find out where the fluid is going. that is the only way the pedal goes down too far. It may not be coming back up because over time brake fluid will absorb moisture and debris will build up. When fluid escapes it allows the piston to travel farther that normal and it will get debris in it and not function correctly. Good luck.

 

That would only jam 1 brake on

 

Sounds like a clutch slave, or as likely the line going to it which is near the exhaust and will fail from the heat, thevslave has a seal in it that also gets affected by the heat of the area. Definitely the first thing to rule out. You can take off the left rear wheel and liner, and the line is mounted on the bulkhead, attached to a hard metal line on one end and the slave on the other. You are looking for wetness or other signs of a fluid leak.

 

Daft question i know but have you checked the pedel return spring is ok

 

The spring should return the pedel on its own, as its big enough