924Board.org

badenkb · Guest

HI all,

My next problem on my projct is the non existent brakes. I 've changed the brake lines, pads, one caliper (the other is serviceable), mastr cylinder - but still have no resistance at the pedal. Bled the system again today with no effect at the pedal.

Is it possible that a failed brake servo would cause this problem ? Or a leaking caliper (the non new one?)

Thanks for any tips

Ian

77 924 NA

Diesel · Guest

NO resistance at the pedal? No, it's not the brake booster. Check for leaks, bad master cylinder, air in the system, pushrod length and brake adjustment.

924RACR · Posted: Mon Feb 04, 2002 8:53 am Post subject:

Highlight the last one!!! It can make a huge difference, can be very poor if your rear drums are out of adjustment. I see you have a '77, most likely you do have drums in the rear. Start by adjusting them. Usually the adjusters are stuck (these are not self-adjusting brakes) and have to be replaced; good news is they're a common VW part from the Beetle, so readily available and inexpensive. PITA factor is that you have to remove the drums to replace the adjusters, but it's worth the work.

What happens is that the stroke of the MC is all taken up by pushing the shoes out to the drum, leaving little or no travel left to actuate the brakes.

First thing I had to do when I got my first 924. Since then I've stuck with disc/disc M471 cars

_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

badenkb · Guest

Hi

Thanks for the tips. I have replaced all rear brake components so the adjusters are free - when I do adjust them - am I looking to just get the rear wheels moving with a little resistance?

Ian

924RACR · Posted: Tue Feb 05, 2002 12:40 am Post subject:

The basic plan is that they will spin maybe 1-2 revolutions before stopping. Just a little drag from the shoes.

_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

numbers · Guest

Follow the Haynes. If you don't have one, you can get them off of EBay for about $5.00 US. It will tell you to ajust them up tight (no wheel movement), and then back each one off one notch at a time until the wheel turns freely.

-nick · Guest

don't even waste the $10 on a haynes. it's online:

http://www.porsche-club.ru//Texts/Haines/0_Chapter.htm

-nick

Roger Hall · Guest

sounds like you replaced the right parts im not familiar with the brakes on my 81 924 but i will be someday its just had for me to imagine any adjustment being that far out to cause a complete loss of braking have you checked the pedal linkage to make sure its attached to the master cylinder and working properly

badenkb · Guest

Hi All

I backed the rear brakes up against the drum so the wheels could not turn to take up any slack in the hydraulic system, but there was still no resistance at the pedal. I 'll check the linkage this evening.

Thanks again

Ian
77 924

numbers · Guest

badenkb,how did your problem start in the first place? Your symtoms really sound like the master cylinder is not working. However, it is very unlikely that a master cylinder would fail while you were doing a brake job. Also, you indicate that you have bleed the brakes. If your master cylinder was not working, you probably could not have bleed the brakes properly.

JvGinPDX · Guest

I just thought I would pass this along as general information. I had some of the same problems you do. My park brake assembly broke loose at the spot welds. About the same time I dropped tehe rear end to remove the gas tank. I thought I tweaked the rear brake hose, because the car needed its brakes pumped twice before it would stop sort of properly. I fixed my park brake recently, and my regular brakes returned to normal at the same time. The brake shoes are pretentioned by the park brake cable, then the brake cylender does the rest.

badenkb · Guest

Hi All

To all the posters who offered help - many thanks - I think I hae sorted the brakes issue. Seems it was a combination of poorly adjusted handbrake and seizing front caliper that was not returning to a rest position and hence pumping the brakes had no effect apart from filling the gap behind the brake piston.A used brake caliper has restored pressure and bite to the pedal.

Many thanks again!!

Ian

77 924 - nearly finished !!