Brake problems

[higgins]

I decided to fit new rear brakeshoes on my 100/6 BN4.

At the same time I had the front and rear drums balanced.

Now that it's all together and adjusted according to the manual, two problems have arisen:

1) The brake pedal goes nearly to the floor. On pumping it two to three times resistance is felt but after about 5 seconds the pressure is gone again (the car does brake but I'm not too keen on risking anything) I found no hydraulic leaks;

2) I am able to pull the handbrake cable all the way up

I definitely need help. /bcforum/images/%%GRAEMLIN_URL%%/confused.gif

 

[Keoke]

Hi Higgins, I do not know why you have this problem based on the repairs you made. However, it appears that you have a failed master cylinder or a wheel cylinder has failed. Failed wheel cylinders will usually reveal themselves by leaking fluid so check all four wheel for a fluid leak.--Fwiw--Keoke- /bcforum/images/%%GRAEMLIN_URL%%/cowboy.gif

 

[Randy Forbes]

Adjust the rear brakes so that the hand brake works. The shoes should just be touching the drums with no drag. See if that lessens the amount of pedal travel.

Now move onto adjusting the front brakes so that all four (4) shoes are just touching the drums, but not dragging. This should also lessen the pedal travel.

If you can now "brake" the car without pumping the pedal, but the pedal goes soft after initial contact, you likely have a problem with the master cylinder (assuming you find no fluid leaking from any of the six (6) wheel cylinders).

Get the mechanical aspect of the system working/adjusted and then move onto troubleshooting the hydraulic circuit.

Re-bleed the hydraulics and confirm the outcome. It can sometimes be a booger to get all the air out of a completely overhauled system, though the front (disc) calipers are more likely to trap air than the (drum) cylinders.

You DO have all the bleed screws oriented to the top, don't you? Seems it's possible to mix up the bleed screw & connecting pipe ports for the twin-leading shoe front brakes...

 

[Dave Russell]

You DO have all the bleed screws oriented to the top, don't you? Seems it's possible to mix up the bleed screw & connecting pipe ports for the twin-leading shoe front brakes...

Interesting point - The older cars had a ball bearing "check valve" under the bleed screw. It supposedly allowed conventional bleeding without having to shut off the bleed screw between pedal pumps. If the two ports are interchanged, it's possible to have the interconnecting pipe between the two cylinders completely blocked off by the ball.
D

 

[higgins]

Thanks for all the info.

I just completed your procedure,Randy.

I did have to adjust the handbrake cable which is now fine.

With regard to the brake pedal travel, it turned out that the front right shoes were not exactly adjusted.

This meant that the cylinder needed to travel further for the shoes to touch the drum and as such more hydraulic fluid was needed in that cylinder to get the shoe right up.

The problem is now solved.

Again, many thanks

 

[Randy Forbes]

Thanks for all the info.

I just completed your procedure,Randy.

I did have to adjust the handbrake cable which is now fine.

With regard to the brake pedal travel, it turned out that the front right shoes were not exactly adjusted.

This meant that the cylinder needed to travel further for the shoes to touch the drum and as such more hydraulic fluid was needed in that cylinder to get the shoe right up.

The problem is now solved.

Again, many thanks

Good!

BTW, I was implying to adjust the rear shoes with the 5/16" square "peg" to get the handbrake to function. I don't know that I've ever adjusted the handbrake's cable.

Just another aspect to fine-tuning the brakes. When all is right, the four-wheel drum brakes do work d@mn well! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif