Looking at these PBR's, I notice that the parking brake would only work decently from a stop. (Holding.)

It doesn't look very useful to slow your car down, and I'm not sure if it could even lock the rears at speed. Looks useless for drifting unless you don't mind changing pads almost as often as tires. (Plus a lot of adjusting.)

How do you guys like your rear disc parking brake performance? Either delco's or PBR's, though I am unfamiliar with the delco's.

Mine isn't finished yet, so I can't really judge it.

Scott

 

Yeah it sucks. Drum rears are much better for drifting since the e-brake locks better (similar to the LS1 rear brake style). I dont even bother using mine with my PBR's, it dosnt lock at speed. You can use the handbrake to extend slides if they lock good. Maybe if it was manual then it might lock with the clutch in. For my track car I'm gonna ditch the OEM setup completely, gonna make a custom hydraulic setup. I'm either gonna adapt a rally setup made for Ford Cosworths or make my own setup with 2 calipers in the rear. Either way, gotta have two master cylinders and some crazy brake line routing.

 

Mine work fine although these aren't really disigned to lock the rears up. A little known fact is that you sometimes need to adjust the "free travel" on the PBRs to get them to contact the rotor correctly. The caliper rebuild instructions cover the steps in detail if you care to read them and have a set on hand. Here's links on how to do it and also where the small (read TINY) Allen screw is that controls that adjustment:

https://www.thirdgen.org/techbb2/sho...ht=free+travel

and

https://www.thirdgen.org/techbb2/sho...ght=adjustment

and

https://www.thirdgen.org/techbb2/sho...ght=adjustment

Ed

 

Thanks for the links Ed! And don't be a stranger now. Come visit our neck of the woods now & then

Anthony

 

Thanks Ed. I've read the one with your pics before.

They work okay, though I might need to adjust it a little better. I doubt they are dragging but I might even need to back out the 3mm screws.

I didn't realize that after '90 there is no ajustment on the cables. (Is that correct?) That would explain why everything I read said there should be one on/near the equalizer, because I was using an '89 service manual as a reference.

I can barely feel the parking brake working from a slow coast, but that's obviously not what they were meant to do. Makes you question your ability to work on the hydraulic side of the brakes when the mechanical side can't save yer ***!

Scott

 

Hey guys, found this interesting thread in the new TGO Brake forum, it has a lot of info about fixing crappy rear brakes.

https://www.thirdgen.org/techbb2/sho...hreadid=272886

 

Yeah Dean is the man but the Mods keep banning him. I wish they would just let him stay. That guy knows his stuff!

 

Yeah, his grasp of technical concepts is awesome, but some guys keep poking at him and he can't restrain himself from reacting, then it's a war of words, sigh. Kinda what happens in any forum discussing cutting an access panel for the fuel pump, heh.

BTW, on the topic of adjusting the rear disk brakes so they're more effective, in your drift care, are you using the 90-92 master brake unit? Which proportioning valve are you using? The 1LE proportioning valve 14089496 [1989 1st design: M1.0 tube nut threads For 1982 - early 1989 applications) or the Wilwood unit...

How about adjusting or removing the proportioning valve springs to raise the line pressure?

Reading the earlier referenced thread, I came to the conclusion that setting up the rear disk brakes to operate at the level of effectiveness desired, is a function of adjusting the line pressure high enough to do so. My ideal in panic braking would be to have the rear brakes lock just after the fronts [instead of the rears never locking].

On a drift car, the ability to brake and lock the rears at any time, any speed independent of the fronts would seem to be the key for the driver to effectively employ understeer/oversteer. I read somewhere that the Hollywood stunt drivers install a "button" to lock the rear brakes in instant on-off to slide the rear whenever the driver wants. Any idea how this would be done on a 3rd Gen?

 

I'm using the stock proportioning valve and MC on that green IROC. Actually everything in that car is stock except for the tranny, the panhard bar, the shifter, the paintjob, and the rear shocks (stock replacement quality). I do plan to modify it further but I wanted to leave it as stock as possible for a while to show that the stock stuff is good enough for drifting. The goal for that green car is to build a domestic drift car for $5000 inc the car and document it on the website for others to see (and hopefully follow). Right now I have around $3800 into that setup, so I hope to be doing some much needed upgrades soon. When I do get around to the brakes I plan to replace the proportioning valve but I'm not sure which one I want to use yet. I'm keeping that car simple and cheap, and I plan to adjust the bias more towards the fronts. This is mainly because its auto so my style of drifting (and use of the footbrake) is different than the manual guys. Not alot of guys use auto's to drift, its usually considered a disadvantage or downgrade. No clutch kicks (initiation technique) and harder to get the E-Brake to lock since you can't disconnect the drivetrain from the engine. So I got a different style than alot of other people, alot of weight transfer and alot of throttle, not as much braking. This makes downhill drifting harder. Sometimes I like to drag the footbrake while on throttle to control the speeds. This is especially usefull in the rain. Right now there is too much bias on the rear for this style of drifting, its causing excessive pad wear in the rear. I agree this is a weird way to use the footbrake, but it seems to suit my style for this car. Most drift cars are 5/6 speeds and the footbrakes are used differently. Instead of dragging them, they lock them, and the bias will determine how the car rotates while locking at speed sideways. My track car will be a 5 speed so I will be setting up the brakes very differently from this green car. I'm assuming my style will change since I will be able to use other techniques, so I want to make sure I set it up with the right equipment. For that car I plan to use the wilwood 6 way lever adjustable proportioning valve and mount it in the car so I can change bias on the fly while drifting. I also plan to do that hydraulic E-Brake setup I was talking about earlier. That button the stunt guys use is probably something similar. Locking the rears does make drifting alot more fun, something I really miss out on in my green car. Its especially usefull to extend slides so you can initiate even earlier than usual and hold it. Makes the drift look much better. But people kinda frown upon using it to initiate the slide, kinda considered uncool.

 

How about an update on your 9-bolt disk brake swap?

Working ok?

Can lock-up the rears effectively?

How was the Wilwood valve install?

 

The Green Machine came stock with PBRs? Not sure of the year of the car, does the car have one of these GM 1LE proportioning valves:

1LE Combo Valve (proportioning valve)

14089496 1989 1st design: M1.0 tube nut threads (For 1982 - early 1989 applications)
10136840 1989 2nd design: M1.5 tube nut threads (Late 1989)
10136840 1990-'92: M1.5 tube nut threads.

To make the back end more "slippery" for drift-style, would using skinny, hard tires on the rear and more sticky rubber on the front be worthwhile? This would enable kicking-out the rear pretty easy...

 

Yeah it came stock with those brakes, lucky me!! hehehe. Its an 89 IROC-Z. It has some good RPO's (L98, FE2, J65) but the rearend ratio is pretty lame 2.77. I haven't checked out the proportioning valve at all yet, all I've done to the brakes so far was replace pads. When I do check it out I'll let you know which one it has.

You're right about the tires thing. Having smaller tires in the rear does make it easier to initiate oversteer, but it also affects how the car slides. Kind of a weird concept actually, once the tire has lost traction and starts spinning, there is still some ammount of friction that keeps the spinning tire connected to the road. If the speeds are too high and the rear contact patch is too small then the car will spin around, so its kind of a balance that needs to match your skill. This is what happens to me alot on the off-camber turn with the smaller width rear tires. The off-camber causes the rear to dip and if the rear contact patch is too small then I instantly spin. And it pisses me off sometimes because I enter the turn just like any other turn and it usually works out great, but never works on the off-camber. Since I'm still a beginner and run lower speeds I run pretty small width rear tires, between 205 and 235. For the fronts I run either 245 or 255. The bigger fronts, smaller rears works good for me at my skill level but if I get better and up the speeds then I'll probably have to change it up. The pro's usually run wider rears than fronts because the speeds are so much higher and they are on throttle majority of the time. One of the things that I've noticed that really helps at any skill level is eliminating sidewall flex as much as possible. When the sidewall flexes it affects the progressive break away or whatever of the tire, kind of throws off the slide. If there is no flex then the tire slides instantly, everything happens much smoother. This is why alot of guys that drift (me included) run stretched tires on their wheels. It totally goes against any concept or theory for racing, but seems to work well for drifting, and it also seems to hold up to the lateral stress. Right now I'm experimenting with 225/50/17's on the rear at 50psi. Looks pretty crazy on a 9.5" wide wheel!! It slides great, feels real smooth.

 

Make sure you check your parking brake cables. I thought it was just because my rear brakes were weak then I checked my cables. Turns out the plastic on the outside of the cable had torn and lodged itself INSIDE of the tubing. Cause one side of my e-brake to not even work at all.

 

My parking brake can't hold the car on any type of incline. I maxed the lever (while the service brake was to the floor) and my car slid all the way down my driveway (after lifting off the service brake). It finally held right before the street where my driveway tapers off. I was in the car the whole time of course, waiting for it to "catch."

So... I can't park on hills anymore without chocks (need to carry some with me now). That pisses me off a lot, I'm going to see what I can do to fix it.

Apparently, there aren't any cable adjustments and I can see every inch of cable and I don't see any damage. Don't have a center console right now, so I can see the lever max out and see the cable pulling.

I still haven't installed the new valves because I don't have the fittings for the front lines. I lost the first fittings and haven't found the fittings I want, so I've been putting it off. Right now, I'd like to just get some flared plugs so I can put the wilwood on the rear.

Either way, they're getting done once I can get back into the shop next week and use their flaring tools.

I need to recheck all four wheels. I didn't slap enough anti-squeak on my front pads and they're annoying me now. Also, one of the rears look like it's wearing wrong. May as well double check the parking adjustment screw.

Can anyone park on a hill with discs? Something HAS to be wrong with my installation....

Scott

 

As far as mounting an adjustable valve inside the vehicle, do you mean just the lever part?

I have the dial valve, and I'd love to have constant control of it, but I don't want to actually mount it inside the cab. I'm not worried about it, and since it'd be raised above the rest of the system (to be accessable while driving) it'd be easy to bleed, but I think it would take too much space.

Has anyone mounted it under the body and ran a cable from the dial up into the cab to control it that way? I'm sure that's what people do rather than actually mounting it in the cab, right?

Scott

 

The iron rear disk calipers on both of my Camaros work ok and the emergency brake levers are not maxed out. This may change when I install the rear PBRs, heh.

According to the Haynes manual, Page 324, the PBR rear brake installation should have no more than 16 clicks of emergency brake handle travel for full lock, using their detailed instructions.

If the handle moves up all the way without effectively engaging the emergency brakes, it's likely either a step[s] in the process needs to be repeated, or a component in the system is faulty.

The "quick fix" at the handle end would be to install a cable adjustment clamp under the car where the emergency brake cables split off to the calipers. I'll bet that '86 Firebird at Fort Shafter has exactly the needed part. However, this approach should not be necessary, according to the book...

BTW, there's a '92 RS Camaro at the FS yard that probably has the correct Master Cylinder required for installation with the PBR rear calipers [90-92 MCs, probably have "FX" label].

 

What year are you looking at for the cables? I've got an '89 manual sitting in my garage that shows a couple adjustment nuts, but my '91 doesn't have anything close to it. There are zero cable adjustments. I'll take a good look at the '86 cables, and even the '92 to see if that looks like my setup.

I'm not concerned with the master in my car now, but I'll rebuild it the moment I know it's leaking. So far, I think it's fine but still needs another good flushing. If you do get rid of your older MC, I'll gladly take it off your hands.

One side of my rear has 40-50% less contact on the rotor. This could be the reason the parking brake ain't worth a crap on my car. I only messed around with one adjustment screw (one side) so this might be the reason.

While the total force is the same on the rotors, the bad side might not have enough friction area to hold and just slips with the other side probably following.

Scott