Front brakes binding

[youngb506]

Noticed recently that when rolling my saloon comes to halt as if the brakes have bee plied but today the pedal is hard and jacking up the front of the car shows that both front wheels are not spinning freely. Any ideas what could be causing this before I start taking the w heels and hubs off? Standard as original 948cc brakes.

[bmcecosse]

First check - is there a little 'free play' at the brake pedal? This is necessary to allow the master cylinder to fully retract and release the pressure. If that's ok - then it will be seized up wheel cylinders. When were the brakes last serviced ?

[youngb506]

It's been two years since brake fluid was changed. An hour later and both wheels are turning more freely. Must be the cylinders, then but It seems unusual that there's suddenly a problem on both sides at the same time.

[panky]

This can also happen if the flexy hoses are collapsing inside - they allow fluid through as the pedal is pressed but restrict it on the way out again and hold the brakes on. Happened to me on a couple of vehicles

[youngb506]

I wondered about the flexible hoses but there's a braided one on one side that's only a couple of years old. The other one is much older. I wonder if one collapsed hose could effect both front brakes.

[panky]

Unlikely, does the car get used often?

[bmcecosse]

If both affected -and then later they come free - it does sound a bit like not enough 'free play in the master cylinder - and is the return spring there (inside the chassis leg) and connected. That could perhaps explain . Less likely I think is a failing master cylinder - but I guess it's a possibility. Check everything else first! By 'serviced' I rather meant - 'adjusted' - is it possible they are just too tightly adjusted?

[youngb506]

It is possible they're too tightly adjusted. But, I don't think I've adjusted them since last summer and I it's only in the last couple of weeks I've noticed the problem. It got worse today. I try to use the car at least once a week for a round trip commute of about 15 miles. I'll try having a look inside the drums for any obvious problem and readjust tomorrow.

[bmcecosse]

Well if it was 'adjustment' it would have shown up a long time ago -and indeed the shoes would have worn down till 'not touching'. So I think you need to look at the master and it's return spring.

[youngb506]

Yes, that makes sense. Not the brake pedal return Spring then? Inside the chassis leg? Where's the return Spring accessed from?

[anthony2]

Have you overfilled the reservoir and retricted the air vent?

[Cornishman]

Dear All,

I have a similar problem with the disk brakes binding. It only happens occasionally. I have checked the rear shoes and front disks and they seem to be ok.
When it happens the brake pedal cannot be pushed.
The brakes suddenly release and everything is OK. Any advice would be really appreciated.

Regards,
Andy

[bmcecosse]

Yes the brake pedal return spring in the chassis leg. The disc brake problem may be because the 'top hat' seal hasn't been removed from inside the master cylinder.

[Cornishman]

bmcecosse,

..looking at a drawing of the mc, what is the top hat seal and why should it be removed?
Do you also mean the pedal return spring?

Best regards,
Andy

[Cornishman]

OK thanks..I have found an older thread regarding this seal.
Once again ..many thanks.

Best regards,
Andy

[bmcecosse]

That seal removal only refers to disc brake conversions - not relevant to drum brake cars. In both cases there must be some freeplay - when the chassis spring pulls the pedal and master cylinder plunger back to rest position, to allow trapped fluid to return to the reservoir.

[youngb506]

After examination, I can see the spring on the end of. The master cylinder is in place and doing it's job. I've taken off one drum and it's clear that the piston in one of the two cylinders isn't going back. Should I remove the post on and clean and grease it with the red rubber grease? I have an ancient sachet of gold coloured girdling brake grease. Would that be OK to use? Can't get the drum back on now to get the car back in the garage!

[liammonty]

It depends how seized it is really. For the price of a set of front cylinders, I'd be inclined to replace them. Get genuine cylinders for the front of you do though, as there are plenty of reports of the pattern front ones failing

[bmcecosse]

Well - if they are 'genuine' cylinders then yes the piston can be eased out and cleaned up - and I suppose your old grease will be fine - provided it really IS 'rubber grease'. If the piston won't move you may need to encourage it with a G clamp or similar - but make sure it doesn't then push the other piston out as you push that one in.