Has anyone tried this yet? The LS1 brakes seem to be the best bang-for-the-buck to fit under stock wheels, and I need a brake upgrade bad. My rear brakes (like so many '88 and older) barely work. They won't even jerk the wheels to a stop when the rear is off the ground (they just kinda slowly drag the wheels to a grudging halt.) The parking brake doesn't work at all, and it's a 6-speed car so I kinda need the parking brake.

Has anyone tried dropping the old iron calipers off their 9-bolt in favor of some 98+ discs? Any tips on what has to be done with the backing plates to accomodate the bearing retainer? Are the tube-flange to axle-flange dimensions even close enough to make it work?

Or am I on untrodden ground here? My searches came up with nothing, which makes me wonder.......

 

The easiest thing to do would be upgrade to the 89 and up PBR style. This is what I did. They came on some 9 bolts so you can bolt them right on with the correct backing plates. They are a real nice setup and work ten times better then the iron 88 and earlier style.

 

Check the following link for more info about PBR's:

https://www.thirdgen.org/techbb2/sho...hreadid=246768

JamesC

 

I know all about the PBR brakes, and I'll go that route if the 98+ brakes don't work out, but I really like the divorced parking brake design so I'd rather do that if I could. LS1 brakes are also a LOT easier to find that 9-bolt PBR's (which are a 1-year option.)

 

PBR's are easily found. As mentioned in the link, they can be had from 89 to 92 and 93-97 (bit different design apparently but still interchangeable) and can be ordered from most 'car places', CarQuest, etc. or, I assume, GM itself. Only the nine-bolt backing plates can be difficult to locate, but not impossible. Again note the link for part numbers and suggestions for the backing plates (if you're interested). The parking brake on my PBR set-up functions fine. You are correct, however, about the design being less desirable than the 98-up version. As I recall, some fab work is required to make the e-brake cable work on the later design.

JamesC

 

talk to ebmiller, i believe he sells the backing plates for the nine bolt. I was going to do the upgrade but lack of funding did me in.

 

I can see installing the LS1s on a 10 bolt, but with the different bolt pattern on the 9 bolts you'll have to either enlarge the holes in the backing plates or redrill them to fit....for that work you'd be better off (IMO) to just go with the LT1/1LE style as they're an easier style to bolt on and will give you great braking performance also. You'd be spending time getting all the parts to fit when you can just bolt the other style right in.

There's also an issue with the LS1s that a few people know about: If you don't get that backing plate PERFECTLY centered on the axle flange, there may be an issue of one side of the internal e-brake drum shoes dragging on the rotor causing heating and uneven wearing of the shoes. This is not a problem with the LT1 style brakes.


Ed

 

I swapped the LS1 brakes onto my last nine bolt. It was a bugger of a job and I would not have done it had I known ahead of time all that was involved. That being said they worked great for the little time I had them on there until the rear broke and now I run an 8.8 Ford hybrid custom rear set up and put the LS1's on there.

To get them on the nine bolt I found the easiest and best way was to file fit the backing plates to fit the bolt pattern on the rear. Slow and labour intensive but very accurate and when it comes to brakes there is no room for shoddy workmanship. Due to the nine bolt utilizing bolt on axles you also must remove the bearings from the axle and make a shim to properly retain them with the LS1 brakes which needs to be about 1/4" thick and install it between the retaining plate and the axle seal. It has to be large enough to fit over the axle and small enough to fit into the LS1 bracket. You will need a press to do this or a friend with one This is necassary because the LS1 backing plates are waay thicker than stock and the axle needs to be held in place firmly so you have to make up the difference with a shim. If you decide to go ahead with it I can give you direction on how to make a shim out of plate steel with a couple of hole saws and a drill press.

As far as the centering concern ed brought up it was no concern to me as the hub shoulder on the nine bolt is exactly the same as the hub shoulder from the LS1 backing plate so mine centered up perfectly. It is a small shoulder but it worked. Mine had the J65 iron discs on it so I cannot say for certain if the drum versions have the same hub shoulder.

Anyways suit yourself but the "old" style PBR 12" brakes work just as well IMO ( I know first hand because I run them on my Players car ) and I would go that route for ease of installation and cost is pretty much the same. The only downside is not having as modern a look as the LS1's. Either way good luck man

EDIT: I could have saved a lot of typing because I just found the link where i posted up about this before. There is a link at the end of this thread that has detailed photos of the spacer/shim I was talking about above.

https://www.thirdgen.org/techbb2/sho...on+a+nine+bolt

 

Yeah...what I said...

Thanks for the info and the link.


Ed

 

87roc....thanks for the link. I read both threads through and there's a lot of good information there. I have both a hydraulic press and a drill press, so I think I'm at least going to attempt this on my RS. If it doesn't work out, no loss, I'll just put the LS1 brakes on the '91 Z (which has a 10-bolt with drums now) and find some PBR's for the 9-bolt like Ed suggests.

Thanks a lot guys, I appreciate the help.

Now to find someone parting out a car.....

 

Glad to help Its fiddly but it worked out okay for me. I just wish I knew then what I know now Ahh thats always the case though... Aside from that the only other mod nec whether you use a nine bolt or not is to fabricate up a bracket to hold the parking brake cables above the driveshaft. Do a search for it here someone posted up pics of a simple but effective bracket. I used to have a link but cannot seem to find it now. Not difficult but nice to see a pic before hand so you get an idea. Other than that I used EBC greenstuff pads. They work very well but dust as much as others. Good luck

 

Dyno Don posted his bracket..


Ed

 

I remember seeing a pic of Don's bracket. Didn't look like it would be tough to replicate. Maybe I can find it again....

 

ls1's should be pretty easy to swap as well