Upgrade drums to LS1 disc brakes for $550 using all new parts!
 

With all my projects lately, I haven't had much time to work on my rear brake upgrade, but I thought I might as well share what I have done so far. The LS1 rear disc brakes will bolt right up to iron caliper and 89-92 aluminum rear disc brakes. They will also bolt to drum rears. Another member has posted an article on how to mod the drum rear in the tech article section on this site. This is for 10-bolt rears. They will fit 9 bolt rears, but since 9-bolts don't use c-clips, some modding will be required that is not listed in my article. Please keep in mind that the article is by no means complete, but I will update it as often as possible when I get new info. So far, the price looks to be approx $550, not including brake pads. This price INCLUDES NEW GM CALIPERS.

Please click the link below
http://members.fbody.com/86firebird/ls1/ls1brakes.htm

Absolutely kewl.....:cool:

Ed

bookmarked ;)

great info.

Ever since you mention this swap in another thread, I've been interested. Thanks for taking the time to put together a website with information. I plan to convert my J42 rears to disk sometime in the near future.

Of course I need to get started on my 1LE project first.
:)

I'm in the middle of converting my 3.73 10bolt over to the LS1 style brakes. How much did you have to give for the calipers? I have a set that went through a fire and need to replaced or rebuilt. Also was there a core charge on the calipers. Thanks Cleve

The calipers were about $60 each and had no core charge.

I have an 89 formula with rear disc brakes already, will I still be required to buy all the components you have listed?

I am also strongly considering replacing my existing rear with a Lt1 or Ls1 rear since mine howls like a banshee as speed. This way I will only need to buy front spacers to run later wheels. In this scenario, I can infer from your info that I won't need to replace the master cylinder or other major components. Is this correct?

Thanks

You should really go with an aftermarket set of brakes like baers or eradispeeds. The ls1 brakes, at least on f-bodys, have a really bad tendency to warp. Mine are warped and have cracks in the rotors with 39k and this is my second set. My friends 02 SS was sent back to the dealer with warped rotors at about 3k. So unless you are just doing this because it is a little cheaper, I would save up and do it right. Just my .02

Yes, even for disc brake cars, all those parts are needed. Everything is different, mostly do to the revised parking brake and thicker rotors. The master cylinder should not have to be changed on J50 drum cars or 89+ prb caliper cars, since they both use the same one to my understanding. The prop valve should be ok too.

If warping the rear rotors is a concern, you could always get powerstop rotors or bear eradispeed rotors for an LS1. They will bolt right up and be thicker then their 89-92 counterparts. Alot of people on the 4th gen boards like the Autozone Aimco rotors since they resist warping more then the stock GM ones, and they are cheaper too.
Any rear brake upgrade for an LS1 can be applied to this conversion. Thats the beauty of it :D Thunderracing lists 52-2302013 Baer Eradispeed (1 Piece) Rotors, 1998-2002 F-body, Rear Pair for $308. If you were to get the parts I listed and instead of getting the Aimco rotors, get the Bear rotors, the total would be $734($550 - 124[Aimco rotors] + $308 [Baer rotors]). $734 for LS1 rear brakes with Eradispeed rotors is a very good price for an upgrade.

$734 for some stock ls1 calipers and baer rotors, or $719 for a complete wilwood kit with much better calipers, etc, which is a better idea ?

Wilwood's Pro Series Rear Brake Kit is available for all 4th gen F-bodies.
Billet 4 piston Dynalite calipers, black anodized and engraved
Integral, two shoe parking brake system neatly hidden behind rotor hat
12.19" dia. vented iron rotors, available drilled and slotted (as shown) or undrilled
Polymatrix High Performance Brake Pads
All kits are completely ABS compatible and retain the stock master cylinder
The optional Wilwood stainless steel braided brake hose kit is also available
Use in conjunction with Superlite 6 Front Brake Kit for the ultimate Big Brake look and unmatched performance, from race-born track-ready parts
Parking brake cable and clevis kits not included in this brake kit. Cable kits and accessories can be obtained from Lokar Performance (865-866-2269) or Gennie Shifter (626-337-2536)

Very good point. I'm sure some members will be using that Wilwood kit in the future. I chose this setup because of the fact that it is factory. I know, people will think I'm insane. BUT the parts are easily obtainable at any dealer or parts store. So if in the future if I need a new rotor or caliper rebuild kit, I can buy it anywhere and at a reasonable cost. Remember, the $734 is with $$$ Baer rotors. $550 is the price with solid rotors. Another option is to get all the parts at a junk yard. $250 is about the going rate. So far, all the people I know who have completed this swap in the past have been very happy with it.

With used parts it seems reasonable, but you still run into the problematic LS1 rotors, and wilwood parts are pretty common, while not at every discount auto, they arent that hard to find, but when going for something like those baer rotors etc it seems like a much better idea to go with the wilwood kit, or the baer copy of the newer J65 brakes to avoid the other problems, im sure the wilwood kit can be had cheaper also, the site i found the actual info and specs on sold the drilled kit for more than the 718 i listed from summit, but they had the same kit with non drilled rotors etc, for 618 or so.

I feel that this is a worth while upgrade for iron caliper and drum rears. And, with the thicker rotors and revised parking brake, an upgrade over 89-92 rears. When using new parts, the upgrade can be had at a very resonable cost.

If anyone plans on using used parts, I would recommend a caliper rebuild and turning of the rotors, along with new brake hoses.

Hey Justin, that web page with all of the info is down for some reason. Can you get me the part numbers for the rear ebrake/backing plates? I need to order these asap. Thanks much.

Seems that server is down.


$61 GM 10434796 Rear LH backing plate with drum parking brake shoes GM
$61 GM 10434797 Rear RH backing plate with drum parking brake shoes GM

When you get the plates, you may have to adjust them so the rotor will fit over them. There is a little wheel on the plates that is used to adj how far out the drum pads go. It's hard to turn as well because it is spring loaded.

Justin,

How did you handle the emergency brake cables? Did you use LS1 cables?

I will be using a proportioning valve for a 91 with 4 wheel disc brakes. Are you experienceing any problems with your drum unit?

Thanks,
BILL

Yes, the LS1 e-brake cables should be used. You'll have to make up a bracket. https://www.thirdgen.org/techbb2/sho...hreadid=156405 has a good pic of a bracket that DynoDon made.

I still need to get some bolts and pins for me to finish the install up. I'll try out the drum prop valve, but I do plan on getting a 1LE 4 wheel disc prop valve, since I'm installing the 1LE front brakes.

I followed the links but could not find details on this swap for drum rears.

As far as I am aware the drum rears have a triangular three bolt pattern for the backing plate which makes this swap a non-starter. Am I mistaken ? Or is there some way around this ?

thx in advance,
RP.

looking good. :)

The flange has to be cut down, then redrilled.
Here's a tech article another member wrote
https://www.thirdgen.org/newdesign/t...reardisc.shtml

Just got the p/n for the guide pins. Its is p/n 12530697 @ $3.60 each.
I'll get a pic up shortly and update the guide.

This looks great.

Post some pics of the install once you start putting it all together.

Robert

Will do. Right now I'm doing the front 1LE conversion. Hope to post some pics of that in a few days.

Just updated the page with the caliper guide pin info and pics.

i lke it, i'm realy liking tese gm upgrades with the brakes.
C5 13"front brakes, and LS1 12"rear brakes. sounds to be alot betta than 10.5" front disc and 10.? rear drum.

I just got the Brakeware kit, H5927. I'll try to get pictures up shortly.

Yeah, it looks like for less than $1000, you could put together a complete LS1 brake system now.


Ed

Exactly what I was thinkng Ed. I'm going out to some junk yards tomorrow to see what's lying around.

Thanks for the writeup!! What a shame; I spent close to that just getting my 82-88 (recalled years) rear discs to work. :(

Webpage updated.

Here's the pic as promised. Only 1 kit is required. It contains enough springs and pin boots for BOTH sides. The GM calipers come with the big middle spring, but not the sides.