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  adjusting the e-brake, parking brake, handbrake on an 88 Fiero

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adjusting the e-brake, parking brake, handbrake on an 88 Fiero by br1anstorm
Started on: 04-25-2008 02:40 PM
Replies: 5
Last post by: 88wht-t-top on 04-25-2008 09:07 PM
br1anstorm
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Report this Post04-25-2008 02:40 PM Click Here to See the Profile for br1anstormSend a Private Message to br1anstormDirect Link to This Post
Well I've searched the forum... and the first lesson I learned is to cope with American English as well as British English! Very important when you try to search for stuff. That explains the title of this post. I know about brake rotors (we call them discs); and trunk (US) = boot (UK); hood (US) = bonnet (UK). Now, what we call the handbrake over on this side of the Atlantic seems to be known in the US as the e-brake (e meaning emergency, not electronic!) or the parking brake.

OK, enough of the linguistic technicalities. Here's the question. How to adjust the e-brake/handbrake on an 88-model Fiero? I have searched the forum, and there's lots of advice, and warnings, about the 84-87 set-up. Because that system uses the e-brake to adjust the rear calipers/pads, the setting or adjusting of the ebrake is critical. The Ogre's Cave article at http://home.comcast.net/~fierocave/brakes2.htm seems to explain pretty well how to adjust the 84-87 system.

In what ways does the 1988 e-brake setup differ? More specifically, can anyone give me a step-by-step guide to adjusting or setting the e-brake (handbrake) on an '88? Can it be done separately and independently of fitting/adjusting the rear calipers? Do the instructions in the Carquest guide at http://www.carquest.com/com...tsTechBrakeT1008.pdf apply to the 88 Fiero setup?

I have to ask the basic questions because my mechanic friend, who has just overhauled the brake system and replaced the pads and all the pipes and hoses (UK) = brake lines (US!), has never worked on a Fiero before, and mine is the only one he is ever likely to see. So we need detailed advice which allows for the fact that we have no previous experience of these weird GM brake systems.

We Fiero owners might be crazy, but at least we're dedicated!

br1anstorm
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Saxman
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Report this Post04-25-2008 04:36 PM Click Here to See the Profile for SaxmanClick Here to visit Saxman's HomePageClick Here to Email SaxmanSend a Private Message to SaxmanDirect Link to This Post
My wife is a Brit so I can provide translations if needed.

As for 88 ebrake adjustment - all I have done is to take up the cable slack at the lower rear of the engine cradle (called crossmember in some places).

I tightened the cable by turning the cable's nut/bolt 1/5th of a turn at a time.
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CC Rider
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Report this Post04-25-2008 04:46 PM Click Here to See the Profile for CC RiderClick Here to Email CC RiderSend a Private Message to CC RiderDirect Link to This Post
I have used both methods and both have worked for me.
When you adjust the cable pay attention to the lever so you do not over shorten the cable causing drag.
Like the carquest instructions said, be sure the dimples on the back of the pads are seated in the pistons.
A shim, like described in the cave, works good as an insurance policy that you have not gone to far.
When you test drive it and find a soft peddle, but your sure all the air is out of the lines, you may need to do the adjustment again.
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br1anstorm
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Report this Post04-25-2008 05:02 PM Click Here to See the Profile for br1anstormSend a Private Message to br1anstormDirect Link to This Post
Thanks, Saxman. They do say that the quickest way to learn a foreign language is to marry someone who speaks it!

I can see that adjusting that nut mechanism (is it called the equaliser?) under the chassis crossmember would be the standard thing for routine maintenance. But if the rear pads have been replaced - which presumably means pressing or screwing the pistons back within the calipers - doesn't that mean re-setting everything, including the e-brake?

I have the impression that you had to ensure that the pistons, pads and handbrake self-adjust screw-thingy within the calipers were correctly positioned so that (a) the rear brakes work properly, and (b) the e-brake also works, not only to hold the car when parked, but also to do the self-adjusting as the brake pads wear down.

I guess what I'm looking for is a detailed explanation, like the Ogre's article on the 84-87 models, of how the '88 rear brakes and self-adjust mechanism works (or at least an idea of which bits of Ogre's advice do and don't apply to the '88)!
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spark1
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Report this Post04-25-2008 05:28 PM Click Here to See the Profile for spark1Send a Private Message to spark1Direct Link to This Post
The caliper lever moves no more than .250" (6.345 mm) off the stop (red line below) to fully operate the piston. The piston moves little more than .020" (0.508 mm) to fully lock the rotor.

The cables only require adjustment to compensate for stretch or if a cable is replaced.



edit: How it works:
 
quote
General Motors' floating caliper rear disc brakes are the most common example of the screw-and-nut parking brake mechanism. The caliper lever is attached to an actuator screw inside the caliper that is threaded into a large nut. The nut, in turn is splined to the inside of a large cone that fits inside the caliper piston. When the parking brake is applied, the caliper lever rotates the actuator screw. Because the nut is splined to the inside of the cone, it cannot rotate so it forces the cone outward against the inside of the piston. Movement of the nut and cone forces the piston outward. Similarly, the piston cannot rotate because it is keyed to the brake pad, which is fixed in the caliper. The piston then applies the inboard brake pad, and the caliper slides as it does for service brake operation and forces the outboard pad against the rotor.

An adjuster spring inside the nut and cone rotates the nut outward when the parking brakes are released to provide self-adjustment. Rotation of the nut takes up clearance as the brake pads wear.


There is much controversy over the last paragraph of the quote. Some say that the parking brake should be used often to keep the service brake in adjustment while others claim itís only necessary to operate it frequently to keep the parking brake in adjustment.

Whatever the case, the parking brake (mechanism inside the caliper) must work correctly when the pads are replaced in order to advance the pads to the rotor. The piston will not advance a great distance by operation of the brake pedal. It will just move out when the pedal is pressed and retract when the pedal is released if no forward resistance is encountered.

[This message has been edited by spark1 (edited 04-26-2008).]

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88wht-t-top
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Report this Post04-25-2008 09:07 PM Click Here to See the Profile for 88wht-t-topClick Here to Email 88wht-t-topSend a Private Message to 88wht-t-topDirect Link to This Post
I recently replaced my pads and also had the e-brake disconnected. To re-adjust the e-brake I needed to pull up on the e-brake handle inside the car, release it and repeat until I felt tension (the e-brake engaging) and release it. This allowed the piston to retract and disengage the brakes. Brakes work fine, both e-brake and regular brakes. The rear brake piston rotates as it moves in and out, thats why you need to ensure the pads are located correcting and the dimples fit inside the indentions on the piston.

John
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