TomP

I posted this on the Suspension board, but didn't get any responses...

I had the back wheels off the car this weekend to re-check the torque on all the bolts that hold my axle on. (Lost a panhard rod bolt while driving, stupid stupid, shoulda checked torque earlier!)

I've been having this problem with "no" emergency brake.. the pads apply, but don't squeeze enough to stop the car. In fact with the handle pulled all the way up, I can push the car in neutral. If I come to a stop, put the trans in park, apply the e-brake, and let up on the real brakes, my car rolls until the trans stops it. Pulling the e-brake while the car's in motion doesn't slow it down at all.

Anyway, so I was looking at my calipers with the wheels off. (The e-brake handle was down.) I noticed that on the caliper I rebuilt (rear passenger), with the e-brake off, the pads were touching the rotor, kind of like the front calipers do. With the Pep Boys remanufactured caliper (rear driver's), the inner pad was 1/4 inch away from the rotor. Is -this- why I don't have an e-brake??

How should I fix this? (OR- is it normal?) Should I remove the cable from that side, and work the parking brake lever until the pad touches the rotor? Or is my caliper not sliding on the bushings? OR, did Pep Boys give me a crap caliper? I knew I shoulda rebuilt that side too!

Oh and yes, I adjusted the parking brake by the book. When I installed the levers to the calipers, they were in the "midway position", then I rotated them back to the stop. After hooking up the cables, I followed: Move adjuster nut until both levers barely move off the stop, then unscrew the nut so they touch the stop. Apply the parking brake lever 3 times, then play with the adjuster nut over & over again until nothing changes.

Thanks!

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

Jim85IROC

iTrader: (2)

That's totally normal. GM only puts rotors and calipers on that side so it won't look funny.


I'm guessing that the caliper is seized, or that awful e-brake adjustment crap is mal-adjusted.

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TomP

Great, now everyone in the office heard me bust out laughing- I'll have to make something up about a spreadsheet problem quick!

I know the caliper grabs the rotor to some extent, as the rotor's not rusty... would a seized caliper do this? Or should I check out those mounting bolts/bushings?

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

Jim85IROC

iTrader: (2)

I dunno. I've had so many problems with my rear disks that I wouldn't walk around calling myself an expert. Mine hardly grab on either side. I've got the POS 85 style brakes tho.

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The IROC Homepage
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View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

Guest

Its the caliper. There is a mechanism inside the caliper that is a one way sorta deal, and usually those freeze up or are broken by someone trying to compress the piston into the caliper without turning it or doing a bunch more work than I would even attempt. Sounds like yours is probably frozen, and thats why its backing off. The self adjustment mechanism inside the caliper isnt working right.
Can you still take it back to the boys? I would.

zz4mula

I have had that problem for years. I got tired and manually adjust them by hand. To do this you will need vise grips and a large flat blade screw driver. It is a given that the rear wheels are off. First clamp the vise grip onto the arm tht the E brake cable is connected to. Take the screwdriver and CAREFULLY insert it between the caliper piston and dust boot. There is a groove there. Prop the screwdriver shaft in a manner that the outercaliper housing itself becomes a fulcrum. Pull hard on the screwdriver(towards yourself) in a manner that would force that caliper piston toward the rotor. Be careful not to pinch the dust boot in the process. Then ratchet the arm with the visegrips clamped on it about three to six times. Repeat as needed on the other side. An old time GM technician taught me this trick years ago. Works for me.

Mike89GTA

zz4mula: Is that an Olympic sport? It sounds like it should be

ws6transam

See my page on upgrading to 1LE brakes. there's a section on the repair of the 1982-1988 rear disks. The balance spring inside the piston's emergency brake mechanism has failed due to insufficent stiffness & corrosion. GM did a recall on those calipers and replaced the piston with a revised design. The TSB is described here:
http://www.isthq.com/~dan/1LEbrake.html


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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines,
5-point racing harness, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Speed-sensitive steering conversion, underdrive pulleys, Crane Hi-6 & more. 1.05g skidpad verified.
New best E/T! 14.400 at 98.6 MPH in 88 degree air at Stanton, Michigan.

Vader

WS6,

You're right - to some extent. GM only included manual transmission cars in the recall regarding frozen parking brake actuator screws. I guess they determined that automatics don't need parking brakes, despite what is written in the owners' manual about alway using them.

The POS calipers were used through 1987 or 1988, I forget which year. They all require constant maintenance to function properly. And you nailed the problem on the head - corrosion and lack of a suitable spring to return the lever.

Parking brakes are one of those things that you shoudl never use, or always use. If you never use it, it will probably stick the first time you do. If you always use it and keep the cables clean, they'll probably never stick in the housings. I always use the parking brake on all my vehicles, and I never have cables seize or stick - just the stupid levers on the rear discs.

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Later,
Vader
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Adobe Acrobat Reader 4.0

zz4mula

lol,,,its much easier on a lift. But in reply to that post of the tech bulletin, only five speed cars were done. I tried in 1991 or so to have the pistons done on my automatic car. GM told me to screw. Even though I had the same caliper as the five speeds they wouldn't budge. That is why I adjust by hand. This condition is worst than the Firestone/Ford problem....LOL

TomP

So basically I should take this Pep Boys Caliper back? I'm rather proud that the one I rebuilt works great... could the PB one have been put together wrong... somehow? Hm. The Pep Boys one even had a piston that looked newer than my original; I assumed they'd have the "correct" piston.

-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

Jim85IROC

iTrader: (2)

As far as I know, the recall did not actually involve replacing the crap with a different design, but simply getting the crap design un-seized or in some way operational again. The recalled cars eventually went south again. My rear disks don't work worth a God-Damn. It took a week of driving before the rust came off the disks, and I still have crap for a pedal.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

TomP

It occurred to me last night that the '84 axle might've already had the recall done to it- Maybe that's why the caliper I rebuilt works so well. Too bad the other caliper was rusted up to hell, I could've rebuilt that one too.

I had the tire off, and was working the parking brake lever (on the caliper) by hand, and saw what you guys are talking about. When I'd swing the lever to push the brake pad to the rotor, the pad would touch the rotor for 1/2 second, then back up. Grr...

At least I know the calipers are working under normal braking.. I put the tire back on, and leaned out of the car so I could press the brake pedal with my toe and spin the tire with my hands. As soon as I touched the pedal, the tire stopped turning, and I couldn't budge it at all. Good to know it's just my parking brake

DBurke, I had emailed you a while ago about the GM part #'s for the recall.. GM wants $99 or so for the piston! That's not a piston I can afford for a while. And it rather bothers me that I might've sent that "recall" actuator in to Pep Boys as my $20 core for their caliper. (Of which, by the way, is already rusty compared it mine. I guess they used a cheap paint.)

zz4, thanks for that procedure; unfortunately since I don't have the i-net at home, I completely forgot what you told me to do! I'll try that soon, and if it doesn't work, the Pep Boys manager will hear from me! (grins)

Thanks!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards