6 replies to this topic

[DrMcNasty]

I have been neglecting my poor car as life has gotten busy. Took it out the other day and the brake pedal has next to no travel in it at all.

I pulled apart the back brakes thinking the emergency brake was binding but it has some slack in it.

It almost feels like when your bleeding and pumping them up to a solid state but it never releases from that state. They still work but have less then 1 cm of travel in the brake pedal before they are solid.

Other then rip every wheel off and disassemble the brakes I don't even know where to start to check it out.

It is a '79 Mini 1000 with all new brake components when I rebuilt the car 3 years ago. Anyone have a thought of what I could check?

I was almost wondering if it could be the brass block on the firewall that is locked to one side but have no idea on how to verify this or how to clear it as I do not have any brake leaks that I can see.

Any input or thought on this is greatly appreciated.

[JonnyBMX]

could the pistons have ceased? how long has the car been sitting

[dklawson]

I would start by evaluating how each wheel "feels". Elevate one wheel at a time, pump the brakes, then immediately turn the elevated wheel by hand to see if it is relatively free. Free means that a rear wheel will be free to turn with some audible scrubbing and stop freewheeling after a bit more than one revolution. Front wheels will have a lot more drag due to the drivetrain but the elevated wheel should be able to be rotated by hand without excessive effort (while the gearbox is in neutral).

If there is no excessive drag found on any of the wheels, assume that the change in pedal travel is purely mechanical and examine the linkage for the pedal and its attachment to the clevis and pushrod for the master cylinder. Look for anything that appears out of place.

You asked about the "brass" junction on the brake lines. I assume you are talking about the PDWA but there are other brass junction pieces used on cars from year to year. If you meant the PDWA, it is a warning switch to tell you when half the brake system has failed. If it had reason to actuate, you would have a warning light turn on somewhere and the pedal symptoms would be just about the opposite of what you are experiencing.

[DrMcNasty]

Thanks for the input.
The car hasn't been driven much ad sat over the winter. I had it out on a drive when these symptoms started.

Inwill check with the car raised and spinning the wheels. I though about the seize aspect but figured of one was seized and the pedal was soft that it should still give me some pedal overall.

When I check it I can get travel for the first couple of applications then I have next to no travel.

[dklawson]

When I check it I can get travel for the first couple of applications then I have next to no travel.

Now that is different than how I interpreted your first post. Combined with the fact that the car has been undriven for a while, that raises some questions.

What year is the car? Have you personally changed the flexible brake hoses? If the car is relatively old and the brake hoses are original, consider replacing them just to be safe. Old brake hoses can appear fine on the outside but the inner layer of the hose can collapse and form a check valve in the line. You can pump the brakes one or two times and fluid makes it to the calipers and wheel cylinders. However, the fluid cannot return through the perished hose and effectively the brakes behave as if they were 'locked on'. This may not be the case with your car but it is something else to consider.

[DrMcNasty]

Doubt it is the lines.
Hand built the car in 2009 and used all new brake components and lines.

Got my new shifter box so I shoul be under the car tonight which means I will be able to check the wheel cyclinders for seizures.

[Shifty]

Brake/clutch pedal pivot pin?