Technical brake pedal too long

[rawill]

Brake pedal question

My brake pedal goes to far in, nearly to the floor, it will not pass a WOF (MOT).
I have checked the pads and linings and adjustment they are all fine.
Handbrake is locked on at 3-4 clicks.

I think I read on here that a faulty brake proportioning valve could cause this.

Can anyone confirm this.

Robin

 

[rawill]

It looks like the friction adjusters are not holding.
I found the LR shoes would not "stay out" the return springs "pulled" the shoes back fully in.

Hence the brake pedal has to go all the way down to get the rear shoes to contact the drum.

 

[rawill]

After replacing the rear shoes because the adjusters were "unadjusting"
Then fitting new rotors and front pads, still no difference.
Then swopping proportioning valves, still no difference.
I mentioned to the mechanic that there was some fluid on the outside of the reservoir, I pumped the brake he checked, and you could see a little spout of fluid from the front piston.

I replaced the master cylinder and now he tells me my pedal is good.
I will get my WOF/MOT tomorrow when he opens.

However!!!!
A strange thing, there was a small "drain hole" under the master cylinder where it bolts to the booster. That let it have a vacuum leak, I plugged it with araldite over night and it was all good.

But what is this hole for, I notice on my other 84 70s it has the same hole, it is a newer master cylinder too. But it never leaked vacuum when I fitted it. I did not plug that hole.

Has anyone got an explanation.

Rbn

 

[Hyperspace]

the hydraulic calipers in the rear wheel that actuate the brakes are only about 10 pounds each, I'd get them replaced, the rubbers are just as tired as your break master's.

 

[rawill]

Do you mean wheel cylinders for the rear brakes. I have rekitted them with new piston rubbers, about a $1.00 each.

 

[Hyperspace]

yes, them, sorry, english is not my home language.
I tried that route but the kit rubbers didn't last long, would have worked out cheaper for me, just getting them replaced first time around.

I did my caclulation wrong, was just under 6 pounds each.

 

[rawill]

No worries about the language.

I do my own work so I will be keeping an eye on them.
And maybe get some new ones and replace them anyway,
it is not a big job.

Thank you for your comments.

I have tried learning Italian, and Czech, so I have an idea of what having a 2nd language might be like.