924 Brake Problem

kbruz · 12-31-2008, 04:58 PM

I have a problem with a 1981 924 and I'm new to the 924 cars (I own an 86 carrera). The brakes travel pretty far to the floor without much resistance, then you really need to push hard to brake.

My guess is that there is a vac leak in the booster or perhaps the brake booster is bad. What else should I check?

924RACR · 01-01-2009, 04:42 AM

Sounds like you have drum rears, which need adjusting; very good chance you'll need to replace the adjusters too. Good news, they're Beetle parts, so shouldn't be so hard to find. Due to the X-split brake plumbing, the rear shoes much engage the drums before you can build up brake pressure. They're also manual adjusting; no automatic take-up, so you will need to learn how to adjust them and keep them adjusted. Or you can convert over to 944 disc brakes.

As for the hard effort to stop, yes, I'd be suspicious of the booster - check first for vacuum plumbing, then see if it's leaking. Another easy test of the booster is to start the engine with your foot on the brake pedal; the pedal should drop a bit when the engine starts. If not, the booster's likely bad.

kbruz · 01-02-2009, 07:40 PM

Thanks for the information. Can the brake booster be rebuilt? Does Porsche sell a kit of any kind?

924RACR · 01-04-2009, 05:18 AM

No, I'm pretty sure it's not possible to rebuild them. Stop in at 924board.org, you should be able to get a used one there...

kbruz · 01-04-2009, 02:10 PM

Great information. I did not know about the 924board.org. Lots of useful information. I sure how lots to learn about the 924 vs. 911.

A couple of more questions about the brakes.

The car does have drum brakes, so looks like I will have to adjust first before I attack other problems. On the 911, the brake switches (two of them) are pressure switches mounted on the master cylinder. What is the situation on the 924. I checked the PET files for 924 and it shows pressure mounted switches, but does not show a part number.

I also read a few posts on the 924board.org that talked about traditional electrical switches on the pedal cluster. What does the 81 924 have?

924RACR · 01-05-2009, 05:32 AM

Both!

The disc/drum setup uses the pressure switches, at least on the early cars. The disc/disc setup or later cars use a switch on the pedal mounting. If your pressure switches have died, it's a straightforward matter to install any generic pedal switch and wire that in - we did this at the racetrack on my '79 (which came with drums).