Write-Up: F-Body Brake Mod

Your going to love it! Its going to feel totally different.

I merged this with the f-body brake thread because I think most of the posts so far are relevant to the write-up. Matthew, maybe when you get to the springs and struts, you can post that info in the respective threads?

Quote :

as far as the drill and tap vs. sleeved...There has been way to many instances to list where the bolts backed out with the sleeve method, bolts loosen the caliper and leaning into the wheel, leading to an extent amount of wheel damage and wheel lockup. Basically the f-body caliper bolts are smaller on the LS1's, with your riviera and my grand prix the bolts are larger, some may argue but the correct way to do your brake swap is to drill and tap your f-body calipers to match the bolts for your stock caliper brackets. Im not sure what size caliper bracket bolts you use but you can take them and your f-body caliper brackets to any local machine to get them tapped to the correct size, for me i spent $10 on the bit, and $20 for him to do the labor, a small price to pay for safety yay

I am seeing some evidence this may be a very real problem. When I had my calipers off last week, I noticed the sleeves were worn inside - there were thread marks. I thought nothing of it, but in the past few thousand miles, I've noticed brake judder getting worse. Initially I thought the rotors were starting to warp, but now I'm not so sure.

The reason I have doubts about the sleeves (and warped rotors) is that my brakes work smoothly sometimes. It seems with very light braking, there is little to no judder. Moderate braking, it gets worse, sometimes very strong. But when I really get on it, the vibration subsides, and I get a very smooth, hard decel.

I tried a few very hard stops from 80+ mph to redistribute the pad compound, but this didn't fix it. Both the rotors and the pads appear to be in excellent shape, and pad/rotor wear is very even all around. I don't think this is from uneven pad compound. It feels like something is loose.

Lastly, I can hear a 'click' sound from the front end when backing up, as I apply the brake. Then it will not click again until I brake going forward. This tells me something is moving - I think it's the caliper. The caliper bolts are tight - tested with torque wrench to 50 lb-ft. If those sleeves are too thin, they may be allowing movement still, and possibly causing the minor judder I'm feeling.

Maybe it's time to order a new set of sleeves to test. If it turns out this is the problem, I will be drilling and tapping my calipers.

I have been noticing the clunk in intial reverse and fwd as well recently. Time to pull them and tap them proper. Never experienced the "judder" under braking but have noticed the clunks usually backing out of my garage...

Eric, maybe check the caliper bolts for tightness. Mine loosened up once, caught me by surprise. If they're tight, probably is the worn sleeves.

Why even take the chance? I'll be tapping mine.

I took the chance because it's a heck of a lot cheaper and easier to use the insert bushings - makes them a true bolt-on mod.

I think I'll be tapping mine, too. But for what they were, the bushings worked well for a while.

$30 ain't much to do a job right IMO.

True, and I do still have my old calipers.

So "now we know, and... (you know the rest)

On the calipers is the brake bleed screw on the top or bottom of the caliper.


I just want to make sure you didn't put them on backwards.

Brakes are working well now, correct?

they were on backwards , but i fixed that after the peddle went to the floor and i couldnt get them to bleed.

i think i figured out the knocking noise. the other night when i took it out i locked up the passenger tire really bad and made a bald spot on it. i think that is the noise i am hearing. i need a new tire.
so everything else seems to be in fine working order except for no abs. the hubs feel ok, but i guess one of the sensors is broke
just to make sure, i dont have to reset the pcm or anything after having the abs unplugged right?

Maybe there's a useful purpose for doing a burn out? Wow, that must have been some lock up!

Is the ABS light on? Mine came on after installing the brakes, I believe having air in the lines will do it. After bleeding with vacuum pump, it went out and hasn't come on since. I didn't reset the PCM.

Just trying to save you a new tire and hub!

well i need the tire anyways b/c i ate through the outer edge b/c i have been needing an alignment for some time now. that is partially why that tire locked up. and yes it was a very long skid down my neighborhood. this was on the first test drive and i had air in the calipers b/c i hadnt swapped them over yet. i hit the peddle, it went to the floor and all of a sudden it got pressure and locked them up at 40mph-0.

good idea on the burnout but i'm almost at the steel now

yes the abs light is on, and so is the trac off light.

thanks for all your help thus far.

How does it feel?

it feels great. i am literally having to relearn how to brake. if i jump on the peddle too hard i have to worry about the car behind me not stopping in time. i feel like i can stop on a dime at low speeds, and high speed braking feels very secure and i havent even tested them to the full potential b/c i dont have abs working.
here are my old rotors and pads full of heat stress cracks compared to the new beasts.




i cant say i love the suspension as much, but i havent really pushed it yet. it does change direction with much less body roll, but it still doesnt handle like a sports car (and probably never will)
i LOVE the new lowered stance. much more aggressive, and the brakes barely clear the rims.

here is a pic of the car all finished. see sig for a comparison of wheel gap.



his asking price seems a little high, but you wouldnt have any down time this way.
http://www.clubgp.com/newforum/tm.asp?m=4833203&p=1&tmode=1&smode=1

Nice find. Are we sure the GPs use the same size caliper bolts as Buicks? I've sent a message to the seller.

In mid Oct last fall, I had the passenger SS brake line (ZZP) burst and fail rather abruptly. You can read about it on page 12 of this thread. I had about 15k miles on the lines when failure occurred. ZZP sent out a pair of replacements, slightly longer, with a newer strain relief design on each end.

Since that time, I decided to drive the car with the old driver side line remaining on the car. I wanted to see if it would fail. This would tell me whether these lines were a defective design, or if it was just a fluke.

Well last week the driver side line failed. It failed the same way, and in the exact same spot. Here is a photo of the two lines that failed, and the new line:



On the left is the passenger side line that failed last Oct. On the right is the driver side line that failed last week. In the middle is one of the new lines ZZP sent me for replacement. You can see how they changed the design of the end. Look closely at the left and right lines - see the point of failure is consistent, only a couple mm difference between the two.

Here is another shot of the three lines. Note the extra length of the new replacement:

Sounds somewhat dangerous - does braking power go to zero when the lines burst?

you can still use the e-brake, but you pretty much have 0 pressure on the pistons if it leaks a lot of the fluid out.

the lines i received are like the ones you got for replacement. i guess zzp stopped carrying the defective ones. (thank god)

Quote :

Sounds somewhat dangerous - does braking power go to zero when the lines burst?

No, braking was fine. But I still consider it to be a dangerous problem. It's the constant leaking that poses the issue.

I would say on a danger scale of 1-10 (ten being life threatening) this would be around a 6 or 7. The lines start to leak gradually, so the red brake light and dinger will let you know when fluid gets about a pint low. Pedal feel is like normal unless you are stopped in gear. You will feel the pedal slowly sink to the floor, like with a bad master cyl. The first line failed quickly, over a couple days. The second one I caught before it got bad, but I think it was leaking for a while, because my first clue was the brake warning light. The system worked fine.

I say 6-7 on the danger scale because these are brakes, and should always be 100% for safely reasons. You can get by for a day or two, but this is a problem that has to be fixed, and it's obviously a DIY job because of the aftermarket set-up. To brake the car, you can do one of two things: 1) use the P-brake to stop the car, or 2) carry a couple pints of brake fluid and add as necessary. I prefer option one, because using the fronts means the leak could get worse, and brake fluid is nasty stuff to have shooting out of your car. But you must put up with constant dinging sound with P-brake engaged, so passengers will be curious - but you shouldn't be hauling passengers if brakes are bad.

Since Oct, the new ZZP line appears to be working fine. I think the added 2" length makes a big difference. It doesn't kink like the old ones did.

Aaron, did you ever run the F body brakes with standard rubber lines? Has anyone else? I want to know how much of a difference in brake feel it would make for me. I have the F body calipers but with the factory hoses still.

Everyone selling the hoses say that they impove pedal feel by themselves but is it really worth it? I'm satisfied with it now but wouldn't mind spending a few to improve it.

The reason I ran SS lines is because neither the OEM F-body nor G-body rubber will work. I figure if you're going to spend extra on aftermarket, might as well go SS braided.

It's more than the vendors saying they make a difference. Talk to anyone who's made the switch and they will say it made a difference. Not a snake oil product, imo. If you watch a rubber brake hose on a motorcycle, you can actually see it expand. Being that our fronts are so long, I think it would make even more of a difference.

And it's not the material, it's getting the right fit. I think these 20"ers will work fine. If anything, SS braided should be more durable than rubber.

AA, did ZZP say the original lines you had problems with were made for the Riv, or did they say "all 3800 cars" or "all G-bodys" or something...? Just curious...

The originals were available in two sizes: one for W-Body, and an extra long 18" version for Bonneville (G-body). The new size for Bonneville is 20.5", so they must have had the same issue as we've seen here.

When I called, they gave me no hassle, "New lines are on the way". I never even returned the originals, and they never asked me about it.