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'76 528 braking issues

Posted: Wed Oct 31, 2012 4:45 pm
by bizz
Hi guys,

So far i've had a pretty good run with fixing up loose ends on my 528. Good fun!

I'm a little stumped by a couple of braking issues:
(1976 528 carb, automatic)

1. the car pulls slightly to the right under brakes. This was far more obvious before I replaced the front calipers/pads & radius rod bushes.

2. I have a mystery fluid leak. I noticed initially it was coming from the master cylinder - i replaced the grommets & the area has since dried up completely. I can't see any other traces of the leak - any ideas?

I have a feeling both issues may be related to the boosters (one not functioning properly?) can anyone recommend an afforable replacement / upgrade? or can/should I overhaul the originals?

Thanks
Ben

Re: '76 528 braking issues

Posted: Wed Oct 31, 2012 5:12 pm
by Blaise
bizz wrote:Hi guys,

So far i've had a pretty good run with fixing up loose ends on my 528. Good fun!

I'm a little stumped by a couple of braking issues:
(1976 528 carb, automatic)

1. the car pulls slightly to the right under brakes. This was far more obvious before I replaced the front calipers/pads & radius rod bushes.

2. I have a mystery fluid leak. I noticed initially it was coming from the master cylinder - i replaced the grommets & the area has since dried up completely. I can't see any other traces of the leak - any ideas?

I have a feeling both issues may be related to the boosters (one not functioning properly?) can anyone recommend an afforable replacement / upgrade? or can/should I overhaul the originals?

Thanks
Ben
The master cylinder can leak into the brake booster. Take a look in there and find out.

My car pulled to the left when I first got it. I rebuilt the calipers and replaced pads and flex lines but it was still there. Only when I had my frame straightened did it finally go away. Take a close look at the frame rails for any crumble areas of distortions.

Posted: Wed Oct 31, 2012 10:00 pm
by Mike W.
With half a dozen hoses and a dozen caliper pistons, there's a lot of places for a little leak. Along with the aforementioned master cylinder. On the pull, start with new or resurfacing the rotors, you mentioned calipers, but not the rotors. Next is the possibility of restricted brake hoses, I had some so bad on a Bav one time I could only get a drip out of them with them disconnected pushing on the pedal hard. Sometimes as they get old they swell inside. Not always, but sometimes. Neither fluid consumption nor pulling should be related to the boosters, but you could be losing fluid into the booster from a bad master. Well, all of that applies on LHD cars, I'm not sure how the boosters interact on the RHD ones but I suspect it all applies.

Re: '76 528 braking issues

Posted: Thu Nov 01, 2012 10:06 pm
by bizz
Thanks guys,
I've ordered new hoses for the front brakes, should have done this initially.
I'll pull the rotors off & get them machined too - I needed the car back on the road so skipped this step when I did the calipers.

While i'm at it I will pull the boosters out & see what's going on. I'm still stumped about the leak, but i have a feeling it's related to the boosters.
Blaise wrote:Take a close look at the frame rails for any crumble areas of distortions.
Frame rails look good to my untrained eye.. was this an expensive fix in your case?