Parking brake question/survey

[Barney Eaton]

I am looking for input on the Reatta parking brake.

If your parking brake is adjusted/working.... you cannot help.

I need input from Reatta owners that have a parking brake that is out of adjustment.

If you can pump your pedal 3+ times and it does not set, then I need you to give me some additional input.

If your car meets the above requirement, I need you to....... jack up one or both sides of the rear.

have a helper apply the brake (not the parking brake)

Now try to turn the rear wheel by hand.

I want to determine if an out of adjustment parking brake affects the normal operation of the rear brakes.

Please answer here with "I can turn the rear wheel" or " I cannot turn the rear wheel"

Thanks for your help.

[Jim]

I didn't jack up the car but the blue '89 I am driving has had a broken emergency brake cable for as long as I have owned it and the rear brakes act normally.

[Guest Squire Tom]

there is no way i am going to try and use the parking brake , too many stories about locking up the rears on luminas etc

91 reatta not TEVES system

[Guest simplyconnected]

I don't have a Riatta, but I can tell you this: The operation of your brake system has nothing to do with your parking brake. As you can tell from others, they either have broken PB's or NO parking brakes.

I had a Ford Escort with parking brakes that stuck fully locked-up. Dealership changed the cable on two occassions, and after another two years, same thing. I personally pulled the drums off, and found the problem in the shoe mechanics, <span style="text-decoration: underline">not in the cable</span>. It was a rust problem that took two years to manifest itself. Most cables now, are stainless steel, in a nylon sleeve (where there is a sleeve).

Don't be afraid to pull your brakes apart and carefully inspect all the moving parts. They are usually simple to understand, and you can take lots of pictures along the way. Don't do both sides at the same time, use the opposite side as a reference.

Your parking brake (formerly labeled "EMERGENCY BRAKE") should always be functional, whether you choose to use it or not.

OEM's have made brakes for a very long time. Shouldn't they be flawless, by now? Modern drum-brake designs are inferior. Where they used to wear down to the steel shoes and squeal like hell, NOW without warning the pistons come completely out of their cylinders long before we're grinding up steel shoes. It disables the car, and causes the owner to call a tow truck and have the brake system fixed immediately.

[Ronnie]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Don't be afraid to pull your brakes apart and carefully inspect all the moving parts. They are usually simple to understand, and you can take lots of pictures along the way. Don't do both sides at the same time, use the opposite side as a reference. </div></div>

Here is a photo of that "simple" system you are referring to. Maybe you should rethink it being simple.

[Guest dpannell]

Barney, I recently bought a 90' that had been sitting for some time.....the parking brake pedal mechanism is rusted (inside the car) and will not allow them to be activated. The rear brakes still work but the pads do not make contact as quickly or efficiently in the brake stroke as they would if they were adjusted properly. Dave

[Guest simplyconnected]

I was hoping someone had a picture, and it's a VERY good one. If you have the other sheet, that shows the NAMES of these reference numbers, that would help too.

It helps to know, as this brake self-adjusts, it turns a jack screw(23) inside the piston-block(19), forcing the piston farther towards the back pad, which 'tightens-up' the stroke. When new pads are installed, the rotation must be reversed, re-turning the jack screw back inside the piston. The emergency brake ratchets the jack screw pushing the piston into the brake pad, mechanically (without hydraulic force).

When we get the proper nomenclature, I'm sure some of my terms will change, but basically that's how it works. No, it's not that complicated, once the mechanics are understood.

If I laid-out a drum-brake and cylinder, it would have about as many parts. Ford Cougars (and many others) use this brake, too. The truth is, only five bolts and one nut hold this entire assembly together. It's a clam-shell, and the brake pads are just 'trapped' inside. When the bolts are pulled out, the pads fall out.

The learning curve isn't that long, and your subusequent jobs go much faster. Just remember, all the adjustment is done between #19 and #23. If they aren't moving, free them up! I like this system because it's a disc brake with an emergency cable override.

[Barney Eaton]

I did not want to bias the response by stating what results I am looking for.

However, it appears that if the parking brake is not adjusted to hold the car, then the self adjusting piston cannot move forward enough to clamp the rear rotor.

I am going to take a second look at a unit and see if I am overlooking something.

[Ronnie]

Barney, It appears the caliper unit is almost identical to the caliper used on an '88 Fiero that I once owned. The main difference in the two are the Fiero uses a lever to pull the cable and the Reatta uses a pedal. I prefer the lever.

It is common knowledge in the Fiero community that if you do not use the emergency brake routinely that the rear calipers do not get adjusted. It also is widely known that the cable and adjuster will freeze up if not used.

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Barney Eaton</div><div class="ubbcode-body">...if the parking brake is not adjusted to hold the car, then the self adjusting piston cannot move forward enough to clamp the rear rotor.</div></div> I think you are attacking this from the cable end of things. Consider this: If one (or both) adjusters aren't working properly, either will cause the cable to be slack. Then, the cable would appear to be 'out of adjustment'. The cable should NEVER go out of adjustment, unless you stretch it, which is impossible. If your cable was properly adjusted when it was installed (PB worked when new), you should never need a cable adjustment again. It's all at the wheels, where self-adjusters compensate for disc wear, AND they return the cable levers all the way. (#3 spring returns #2 lever.)

<span style="font-weight: bold"><span style="color: #660000">You're right. If the levers never return, the self-adjusters will adjust to that position, and you would never know different by pressing your (hydraulic) brake pedal.</span></span>

The parking brake should stop your car from any speed. Lever, pedal; it doesn't matter how you pull the cable. It should still stop your car, and HOLD it from rolling down any steep grade. That's how it worked when it was new.

[Vincent Vega]

It always amuses me when people say they never use the parking brake.(They always refer to it as the "emergency brake") because it doesn't matter. They wear out from non use faster than regular use. On most front wheel drive cars it "is" the rear brake adjusting method. Reatta included. Plus, It really takes some strain off the trans linkage and parking pawl if it is applied before the car rolls to a stop. It's a parking brake first, then an emergency brake. Don't wait for an emergency to figure out it doesn't work. Use it regularly.

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Vincent Vega</div><div class="ubbcode-body">...It really takes some strain off the trans linkage and parking pawl if it is applied before the car rolls to a stop. </div></div> Right on, Vincent.

I can't count the number of times I pulled the parking brake (and the release at the same time) while I was rolling, just so the brake lights wouldn't come on. (Like when I didn't want to draw attention from a cop.)

I never had a problem with my parking brakes because I used them all the time. It comes from my stick shift days. If my car was on a grade, the only way I could step out and keep the engine running was to set the brake. Thank God, I never had to use it for an emergency. Rear brakes don't stop very fast, even if you lock up the back wheels.

[Ronnie]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> I was hoping someone had a picture, and it's a VERY good one. If you have the other sheet, that shows the NAMES of these reference numbers, that would help too.</div></div>

Here you go:

[Phisit]

My emergency brake doesn't work at all, never has. Funny you should ask though, I am relacing the rear pads, and the passenger side one is fully extended.

How do I remove the nut holding the lever? I have tried very hard to move the nut, but no go.

Any hints?

[gr8scott]

Speaking of parking brakes, my 89's will set on the third pump of the pedal. Is that about normal?

[Barney Eaton]

The owners manual says up to 3 1/2 pumps

[JeepNut]

If it's not too late for you the adjuster for the parking brake is under the driver's side of the vehicle. It's a black tubular looking thing with a nut on the rear end side tapering to the foot pedal cable. Hold the rear cable on the squares and turn the nut clockwise, 5/8" open end, to take up the slack. Or that piece is broken GM # 25515644 (adjuster) 78 05105A. Just replaced one.

good luck,

Martin

[Guest Bobby Valines]

I'm thinking i would be a perfect candidate for your survey. My brake peddle is a little low and I have been afraid to try the parking brake. Its been stopping OK but could be better.( OK do I have this right don't touch the parking brake just have a helper push on the brake normally with motor on or off)

[Guest kennyw]

This is a terible brake set-up. I even found the square tool to screw the thing back in place. My cable is hanging now. When I first bought the car I went through the assembly drill. Getting the slider pins to work. Even taking the lever off to get both side pulling at the same time. Both of these things can cause the pads to just touch one side of the rotor. It is high maintanance to keep this system working like it should. You can tell that from the posts above. A screwing system to set the parking brake. I wonder what they were drinking the night they did this design..........ken

[jonlabree]

It's been that way for years.

[Guest steakneggs]

I started a thread on the Steakmobile's PB issues a few months back that was unresolved. The left side does not work at all. It has something to do with the actuator rod or self-adjuster. It is not doing it's job. I think it is frozen to the piston instead of unscrewing slightly (to clamp the piston). I think that it is rotating the piston, if that is possible. The arm reaches full travel without doing any braking. I need to pull that caliper off to see if the piston rotates when the PB is applied. Steak

[Guest steakneggs]

Barney, see if the lever (on the caliper) moves to full or almost full travel with 3-4 pumps. Compare the two sides. If it does then the adjustment is correct and something with the actuator rod is not working. Steak

[Ronnie]

These parking brakes are the same design used on the 1988 Pontiac Fiero that I once owned. It is common knowledge in Fiero circles that if you do not use this type of parking brake system that they soon get where they will not work.

I highly recommend that if you have a parking brake that works that you use it on a regular basis to keep it working.

The Fiero had a lever to pull to set the parking brake but the calipers operated the same with the piston ratcheting forward each time it is used to keep the parking brake in adjustment.

They freeze up due to corrosion and getting gummed up if they are not used.

[Guest steakneggs]

This system looks like the one on our '93 Regal. The only way I could get the piston into the caliper when replacing the pads was to remove the lever so that the actuator screw could rotate. I learned about this method in a Haynes brake manual I read in a parts store. The Reatta FSM doesn't say anything about any special procedures to push the piston in, including using the rotator tool. (I'll check again). I wish someone on this forum would disassemble a bad caliper and figure out how the actuator gizmo reajusts itself for pad wear. Steak

[Barney Eaton]

I have studied a Eldorado caliper which is the same design used on all GM cars with rear disc during that period.

It appears the adjustment is friction. It's difficult to explain, so here is a picture of the rear piston taken apart. You cannot buy the internal pieces, but you can take it apart and clean it.

If you do, start by measuring how far the cup thing with hole on the right side sticks out past the back of the piston. To take it apart, blow compressed air into the rubber plug on the front of the piston. Have it against your bench or somewhere parts don't fly across the room.

The adjustor has a seal around it and normal breaking pushes it forward against the piston and pushes the piston out against the pad. That little metal stamping that attaches to the front of the piston and the back of the pad, keeps the piston from turning, otherwise this design would not work.

The "T" shaped cylinder with the spring around it fits into the scollops on the adjustor. This assembly screws on the parking brake screw.

When you pull the parking brake lever...it turns the screw...which pushes the "T" shaped cylinder against the adjustor....which pushes the piston against the brake pad. Simple when it is working.

As the pad wears...the piston does not retract as much... leaving a gap between the inside of the piston and adjustor. What is SUPPOSED to happen when you apply the parking brake is the adjustor will turn until it hits the piston...self adjusting itself. If the inside of the assembly is dirty, rusty, etc either the adjustor does not turn or most likely, it gets stuck to the piston and no gap is created, so no adjustment happens.

The adjustor can move over 1/2 inch on the "T" shaped part so the rear brakes continue to work but the parking brake becomes out of adjustment.

[Guest steakneggs]

Thanx for posting those pics, Barney. They are not shown in the FSM. The piston, adjuster and T shaped thing are called the "piston assembly". The leftside PB on the Steakmobile must be suffering from a stuck adjuster. I messed with it today. If I put a wrench on the lever nut and pull it forward the brake will hold. But it is so far in it's travel that it is arcing downward, past where the cable pulls from. I tried resituating the lever on the actuator but it is in 60 degree increments for the hex shaft and doesn't allow any good adjustment. I pushed the piston in a little to get a better adjustment but the result was the same. I guess I'll live with it. Does your's do the same thing? Steak

[Guest Bobby Valines]

Wanted to help with your survey but couldn't get a helper for a few days. So i thought I would try the parking brake adjustment thing and it worked. My brake peddle went up, after I drive to work about 10 mi. ill touch the back rotor to see how hot it is, but i think its ok.

[Guest steakneggs]

Today I'm going to push the piston all the way in then push it out using the lever to see if I can free up the reset mechanism. Steak

[Ronnie]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steakneggs</div><div class="ubbcode-body">Thanx for posting those pics, Barney. <span style="color: #FF0000">They are not shown in the FSM.</span> The piston, adjuster and T shaped thing are called the "piston assembly".</div></div>Scroll about halfway up this thread and you will see the complete parts breakdown for the rear caliper that shows all those parts. It came from the FSM.

[Guest steakneggs]

The FSM shows the piston but does not show the two additional parts that are inside it, which is the ones I was curious about. From the FSM picture it looks like the actuator rod screws directly into the piston, which it doesn't. It screws into the T shaped thingy (that we don't know the name of because the FSM DOESN"T MENTION IT), which sits in that other piece that we don't know the name of either for the same reason. These two parts are at the root of the probs with my PB and probably most Reatta and similar units in cases where the lever moves but provides no braking. Steak

[Ronnie]

The reason those "T shaped thingy" are not in the FSM may be because they are not Reatta parts. Barney can probably clarify this but I'm not sure in his post we are looking at a photo of Reatta parts. He starts out by saying "I have studied a Eldorado caliper" and then refers us to the photo in question. Is it Reatta or Eldorado photos?

As you can see in the photo below of the '88 Fiero it is very similar, although not identical to the caliper shown in the FSM. It is accurate. I know because I've had the Fiero calipers apart. I know for a fact that it works just fine without the "T shaped thingys" Just because there are no "T shaped thingy" shown in the FSM or the FSM photo I provided doesn't mean the FSM is wrong. I would bet on it being correct.

[Guest Squire Tom]

i have never used the park brake , even after i replaced the rear leaking caliper. if something goes wrong with the park brake and it locks up , is it an easy fix to free the rear brakes , or do we need a rollback tow ?

[Guest steakneggs]

If it locks up due to a stuck cable it could be pryed rearward or unhooked at the lever by each rear wheel. I don't think that there is any other way it could lock up. Steak

[Guest steakneggs]

I guess we'll never know for sure until somebody guts a Reatta caliper. It doesn't make any sense for the manual not to show all the parts particularly if it might be something that might need servicing. It also would be difficult to explain how the actuator screw would compensate for pad wear if it simply screwed into the rear of the piston as the FSM and yourself would have us believe. It also raises the question why the piston is refered to as the "piston assembly" in both the Reatta and Fiero manuals indicating there's more than one part to it. I might also point out that the FSM does not show the internals of the Teves when it is obvious that it comes apart. Steak

[Barney Eaton]

Ronnie, I suspect all the GM rear disc of the time were alike. Tomorrow I may attempt to take a picture that shows the piston better.

The exploded view you posted of the Fiero does not show the thing I call the "T" part because it is inside the piston (#17) and since it is sold as a unit, all the internal parts are intentionally not show...GM did not want you or the service guy spending time trying to get them to work.

[Barney Eaton]

Ronnie, I suspect all the GM rear disc of the time were alike. Tomorrow I may attempt to take a picture that shows the piston better.

The exploded view you posted of the Fiero does not show the thing I call the "T" part because it is inside the piston (#17) and since it is sold as a unit, all the internal parts are intentionally not show...GM did not want you or the service guy spending time trying to get them to work.

[Guest steakneggs]

Why wouldn't GM want the service guy to have full knowledge of the internals of something he might be repairing? Especially since the ommitted parts are the most problem prone? I can't believe that their interest in selling a new caliper would be evident in a FSM, although it obviously is with the Teves. Steak

[Guest Greg Ross]

From what I remember of that era of GM, Rear Calipers were a constant problem on GM Models. In my hundreds of thousnads of miles on this Reatta of mine I've rebuilt the rears many times. I'm going to say I have replaced rear calipers at least 3 times. And they got serviced in between, new pads, lubed the sliders etc, and adjusted the Emerg. Brake links to try and keep them quiet.

[Barney Eaton]

I don't believe it was ever intended to be a servicable part. At todays shop rates, it could easily take the tech longer to disassemble, clean and reassemble than the cost of a new piston assembly....

I am attaching a sketch that may better illustrate the parts inside the piston.

The Retainer holds everything inside the piston, it is pressed into the piston. by applying compressed air into the hole in the face of the piston..it will push the retainer out...again be careful because the compressed air can cause all those parts to shoot across your garage.

Note that the head of the "T" nut fits into teeth (I called them scollops earlier) on the inside of the adjustor. There is about 5/8 inch of travel between the "T" nut and adjustor which allows the rear brake piston to continue to function when the parking brake is no longer in adjustment.

Operation.....when everything is adjusted properly (like new)..

* Pushing the parking brake pulls the lever, which turns the adjustor screw.

* That pushes the "T" nut toward the piston (brake pad)

pushing the adjustor and piston forward.

* as the brake pad wears, both must travel further and instead of just pushing, it slips a little because a small gap is created between the end of the adjustor and piston (note the bevel on the front of the adjustor and matching bevel on the piston)

* When everything is clean inside the piston, the adjustor turns slightly with each parking brake application, keeping it in adjustment.

[Ronnie]

Barney, I remember when I took the Fiero calipers apart that on of the adjustment screws had left hand threads either on the larger, coarse threads, or the on threads for the nut that holds the lever on. I'm sure the Reatta will also have left hand threads on one of the screws.

It has been 10 years since I had the caliper apart and I can't remember for sure what parts had the left hand threads. Do you know which threads are left hand?

It would be good information for anyone who wants to take their caliper and piston assembly apart, without damaging them, to know.