Grinding Calipers 101
Definitely a nice write-up, we need to keep it somehow.
I will post pics of my rear calipers, I just went drag brakes, but my rears look like that and I put 20,000 miles on them. But I can see where one could break, it could happen especially in the center part where it's most thin.
I will post pics of my rear calipers, I just went drag brakes, but my rears look like that and I put 20,000 miles on them. But I can see where one could break, it could happen especially in the center part where it's most thin.
thanks for the writeup, but unfortunatly I didnt see this post wed or fri when I was doin this work. I'll post a couple of pics when I get a chance. I had to go a little deeper, not sure if the aftermarket rotors are a bit thicker, and I replaced the brake pads cause they were worn down, and that moved the caliper back outboard. once I put the new pads on, had to start grinding heavy metal all over again. I did the paint/bolt on wheel/grind/paint/boltonwheel......... so I know I only took off what needed to be to get it to clear. oh, also I used a 3/16" spacer cause I REALLY didnt want to grind bills calipers any more then they are. that post about the guy crashing because his caliper broke is scaring the hell out of me for Bill. really.
One thing I didn't see mentioned (and I learned the hard way) is that you need to make sure you have a little extra clearance as the metals expand when heated. I grinded (ground?) my calipers to clear my Pro Stars, drove the car for several weeks with no issue, and made one pass at the track. After that pass (mid 11 at 115 or so) I got on the brakes and after a second or two felt and heard a loud thumping sound. It sounded exactly like I blew out a front tire. I limped it onto the grass on the return road and got out, but no flat tire. I got back in and the noise was gone. I looked closer back in the pits and the caliper got into the backside of the wheel pretty good. It was fine for normal driving, but slowing this tank down from 115 MPH got them expanded enough to make contact.
yeah, that was another reason I decided to go with a spacer. I pretty much had them clearing w/o the spacer, but knew I needed some gap between them, thats when I said fine, atleast now I'll' have this much clearance.
What do you guys think about the wheel studs that come standard on the Moser 9" hardened alloy axles? Do you think they have the tolerances to hold up to track passes on slicks? I will replace mine with longer ARP studs eventually, but I can't help but wonder that if you are buying an almost indestructible rear end setup, you would think Moser would install ARP quality wheel studs on the axles.
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Suggestion; Change your brake pads while you are at it.
If you grind based on worn pads and come back later to install fresh pads, you
will find that you have lost clearance between the calipers and the rims.
Not the best of surprises on race day morning when you are switching to your
track tires for the first time since changing your pads.
If you grind based on worn pads and come back later to install fresh pads, you
will find that you have lost clearance between the calipers and the rims.
Not the best of surprises on race day morning when you are switching to your
track tires for the first time since changing your pads.
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Joined: Aug 2006
Posts: 502
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Has anyone tried to see if W-body calipers can be swapped over to overcome this problem? I know F-body calipers and rotors are a direct swap to W-bodies (popular brake upgrade). I'm pretty sure you can swap both the rotor and the caliper with no problem (aside from not having as much braking force), but I'm curious as to whether you can use the W-body caliper with the F-body rotor. As for not having enough braking force with the smaller rotor and caliper, I can lock mine up at any speed (anti-lock disabled) with just upgraded Green Stuff pads. And the W-body weighs in at about 3500-3600lbs. So, needless to say, if you are looking for something that would work for street/strip, I'd say you would be just fine. Now, if your road racing (which would be silly with drag wheels on there anyway) it probably wouldn't be a good idea. It would also be a small weight savings, too, from the lighter rotors and calipers.
Originally Posted by Dan Stewart
Has anyone tried to see if W-body calipers can be swapped over to overcome this problem? I know F-body calipers and rotors are a direct swap to W-bodies (popular brake upgrade). I'm pretty sure you can swap both the rotor and the caliper with no problem (aside from not having as much braking force), but I'm curious as to whether you can use the W-body caliper with the F-body rotor. As for not having enough braking force with the smaller rotor and caliper, I can lock mine up at any speed (anti-lock disabled) with just upgraded Green Stuff pads. And the W-body weighs in at about 3500-3600lbs. So, needless to say, if you are looking for something that would work for street/strip, I'd say you would be just fine. Now, if your road racing (which would be silly with drag wheels on there anyway) it probably wouldn't be a good idea. It would also be a small weight savings, too, from the lighter rotors and calipers.
Interesting.....
So do the common drag wheels clear the W body calipers?
very intersting indeed. if rotors can swap, then that means the same bolt pattern. maybe I can try to take one of my drag front rims to work and next time Im doin a brake inspection, see if it'll bolt up? you are talking about the 99-up w body's right Dan? not just the 5.3L gtp's with the braking package? if there smaller diameter, I bet it'll clear with just a spacer like the LT1's.
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Joined: Aug 2006
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Originally Posted by Irocss85
very intersting indeed. if rotors can swap, then that means the same bolt pattern. maybe I can try to take one of my drag front rims to work and next time Im doin a brake inspection, see if it'll bolt up? you are talking about the 99-up w body's right Dan? not just the 5.3L gtp's with the braking package? if there smaller diameter, I bet it'll clear with just a spacer like the LT1's.
I'll go ahead and post the link to the post on clubgp with the instructions and you can look it over yourself and see if it might be feasible to retrofit.
http://www.clubgp.com/newforum/tm.as...mode=1&smode=1 WARNING!!! NOT 56K FRIENDLY!!!
If you look at the pics, you can see that the caliper does not stick out as far on the W-body caliper in either x or y, so I would guess you shouldn't have to do any grinding.
Last edited by Dan Stewart; Aug 18, 2007 at 12:03 PM.
oh snap
I didnt think of that. my Z is still stock. But I have lots of gtp ****. Ill have to cheak this.
youd have to drill out the braket holes on the LS1 car. Ive done alot of these swapts on gp's But the pedal sucks, so I dont really like it. The GP master is to small. On a GP the flex line is really tight with the LS1 caliper. So I bend the line braket a bit. When you get a GP caliper on you LS1 car, your gona have more flex "loop". So cheak it for rubbing the wheels, or cheacking anything. The flex line will now be like 3/4-1 higher up the smaller caliper.
Maybe Ill be selling the gtp with LS1 brakes.
I didnt think of that. my Z is still stock. But I have lots of gtp ****. Ill have to cheak this.
youd have to drill out the braket holes on the LS1 car. Ive done alot of these swapts on gp's But the pedal sucks, so I dont really like it. The GP master is to small. On a GP the flex line is really tight with the LS1 caliper. So I bend the line braket a bit. When you get a GP caliper on you LS1 car, your gona have more flex "loop". So cheak it for rubbing the wheels, or cheacking anything. The flex line will now be like 3/4-1 higher up the smaller caliper.
Maybe Ill be selling the gtp with LS1 brakes.
Last edited by studderin; Aug 18, 2007 at 08:58 PM.
Originally Posted by 01_ram-air
As was previously stated, it has nothing to do with offset. These cars come stock with 17" rims. The brakes are big but had plenty of clearance on a 17" rim. You can put a 16" rim on also with no issues. However, the 15" rim is too small to clearance the brakes.
You did bring up a good point that I left out and that was backspacing...
15x8 rim you want to run a 5.5" backspacing
15x10 rim you want to run a 7.5" backspacing
15x3.5 rim you want to run a 1.75" backspacing
If you get a narrowed rearend then you have different options for backspacing.
You did bring up a good point that I left out and that was backspacing...
15x8 rim you want to run a 5.5" backspacing
15x10 rim you want to run a 7.5" backspacing
15x3.5 rim you want to run a 1.75" backspacing
If you get a narrowed rearend then you have different options for backspacing.
yes but its not the backspacing that makes it atight fit. its just the diameter of the rim and the way they shape the wheel where it transitions fom outer rim to flange area that makes the prostars so much tighter then other rims.
you would still have to grind, just nowhere near as severe. I got a pic of mine somewhere. so no worry of breakage, but you still gotta do some work.
I'll throw a pic up here when I get home later.
I'll throw a pic up here when I get home later.
started my caliper grinding.... i like how the 5.5 inch back spacing will tuck but i HATE the grinding so far. i took a good bit of material off so far and no where near finished. i think i may go with a spacer too.
what about wheel studs? do i need longer studs? these wheels will only be mounted for track use, and never see road time (rarely). so i need my stock wheels to go back on and stock lugs to fit
what about wheel studs? do i need longer studs? these wheels will only be mounted for track use, and never see road time (rarely). so i need my stock wheels to go back on and stock lugs to fit