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isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

Well, I got the car to move under its own power. I replaced the rear shocks, rear wheel bearings (both R & L), new drum brake hardware, new shoes, drums turned, wheel cylinders rebuilt, CVs repacked and new cv boots/bolts. The drums/shoes are adjusted correctly and the brakes were bled after everything. The only thing is that is bothering me is the brakes don’t seem to work as well as they should. I drove down the street a little bit and hit the brakes and slowed a little. The brake pedal went down with little resistance compared to how much it should have. I am at a loss. Any thoughts as to what to do next?

Thanks,
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I would probably start by going back to readjust ther rear brake shoes. Yeah, I know you say you adjusted them. But, they don't center themselves on the drums very well, and your drums are now larger than they used to.

After you step on the brakes a couple of times, real hard, the show will center themselves (oops, you already did that), and the shoe clearance will have opened up, which will give you a soft pedal.

How much brake fluid to you run through the bleed valves when you were bleeding the brakes? I use close to 32oz when bleeding both the front and the rear. About 1/2 of that when doing one end of the car. Maybe you didn't run enough brake fluid through to wash out all of the air out of the wheel cylinders.

Did you bleed the front too?

Stampedetrail · Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska

Just 2 + 1 things:
either the system hasn't been completely bled, i.e. still air in the lines possibly between the MC and the rear drums, and/or the rear drums are not adjusted fully. OR there's a leak in the system. Check the level at the master cylinder & check for leaks everywhere, then (if you find nothing) re-bleed, then re-adjust.
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1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can.

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

I will bleed them some more tomorrow and adjust if necessary.

EDIT: I bled all the way around and checked the adjustments. The shoes are adjusted. Everything seems like it should work. I will try driving to work tomorrow to see if they work.

Could there be an issue with the brakes working if the rears are adjusted too much?
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

I have bled everything, and the rears again. I checked adjustment and they seem fine. I still have issues with braking. One thing I noticed is that while bleeding, the rear bleeder valves leak when I am using the hand vacuum pump, the valve can move slightly allowing air to move into the hose. I now have all clear brake fluid. Would a new bleeder valve help with the air leaking? I don't think the valves leak when closed.
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

Ozzie · Posted: Tue Aug 01, 2006 11:20 am Post subject:

If fluid is coming out of the rear cylinders around the thread of the bleeder you can guarantee air is getting in.
Replace the bleeder and if no joy, replace the cylinder/caliper.
When bleeding you only have to open the bleeder a little.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

Where would the best place to get the bleeder valves be? I will check with the dealer tomorrow.
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

Ozzie · Posted: Tue Aug 01, 2006 12:47 pm Post subject:

Any brake shop should sell them or go to an online shop like Paragon.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

I ordered them from the dealer as they were roughly the same as at parts stores.
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

Last night, I adjusted the drums as far as they could go, then backed off slightly. When I drove the car today, it seemed to stop better and have a firm pedal. Not as firm as it was, but a noticeable improvement. I then adjusted as far as it could go, then backed off again. I noticed both backing plates were warm or hot to the touch. I will drive the car tomorrow to see if the car is back to normal. Just thought I'd give an update. My only fear is that the shoes would be too tight and would drag while driving. How likely could this be?
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

Ozzie · Posted: Fri Aug 04, 2006 1:15 pm Post subject:

It happens and you'd notice.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

isuras2 · Joined: 17 Jun 2005 Posts: 458 Location: Phoenix, AZ

I know the brakes get hot with use, but with the shoes correctly adjusted, should the backing plate get hot?
_________________
Rob
'80 931 (sold)
'80 924 NA (sold)
Former Omaha Crew

Ozzie · Posted: Fri Aug 04, 2006 11:36 pm Post subject:

They'll get fairly warm.
Discs get very hot.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance