Hassle free drum rear disc conversion to 1LE/ LT1 PBR rear brakes - Third Generation F-Body Message Boards

ebmiller88 · 05-14-2007, 11:10 PM

First off, sorry to all those I have yet to get back to. I am trying to catch up with PMs and e-mail as best I can. Please be patient and I'll get back to you.

Now, as promised here's my thread on the hassle free rear disc conversion for drum rear cars. NO cutting or drilling or mods of any kind involved, just a couple of hours to do the swap. You'll need the brakes, basic hand tools, some penetrating oil, and that's about it. This swap is for 11.6"-12" rear PBR discs on virtually any drum rear F-body and I'm sure a few more cars out there, specifically S10s and B/G bodies with rear drums. I'll do my best to explain it all along the way.

Get the rear in the air and start by removing the wheels and all the outer drum brake hardware and such, and remove the e-brake cables from the connector above the driveshaft. You'll also need to drain the differential fluid and pull the center pin out of the carrier so you can get the axles out. Here's the new backing plate next to the mod test axle, a stock 10 bolt open drum rear:

Once all the drum brake stuff is off, loosen up the stock brake line as it goes into the wheel cylinder with a 12mm crowsfoot wrench. Soak it generously with penetrant before you start and it will come loose easily. You can pull the rear axle at this point and give the lube some time to work.

Use an awl or an ice pick to remove the clip that holds the wheel cylinder to the backing plate

Use a big breaker bar and a 21mm socket to remove the wheel cylinder bolt. It is ON THERE, it's a bear. Hold onto the other side of it with a large Crescent wrench or equivalent.

Once the wheel cylinder is off, remove the lower two bolts holding the plate on with a 10mm wrench/socket

Now you have the bare drum flange ready for the new plate.

Slide the new backing plate onto the flange and install the large upper bolt and two lower bolts in place. (One of mine broke off and is not seen in the pic). Reinstall the axle and cover plate now, and refill the diff with new gear oil. This would also be a great time to replace the axle seals and check the bearings.

Slide the new rotor on and bolt the caliper in place using the supplied bolts

View from the backside:

Top view. Rotor is slightly askew but is fine when tightened down right, I had the lug nuts loose.

All in all a very easy swap to disc brakes and keep your stock rearend gears and not have to pull the whole rearend. I will have plates for discs ranging in size from stock 11.6" to custom 13" two piece rotors I will be offering soon. Again, all this is bolt on stuff with no mods required.

You will also need to 1- modify and/or bend the stock drum axle brake lines to work with the new discs or 2- buy new disc axle brake lines which is what i recommend.

Another thing to note. There is the possibility that the axle flanges on some axles will not sit flush against the inner face of one type of rear rotor used with these brakes. They have a larger outer diameter than the rotor has in inside diameter. If this is the case, there is another rotor that will work with these brakes, used on early LT1 4th gens and I can tell you what part to get should you have an issue. I'll post a pic of that rotor later in the week.

Any questions, please e-mail me or PM me and I'll get back to you as soon as I can, sorry for any delays.

Ed

klause83z28 · 05-15-2007, 12:08 PM

When you say early lt1 4th gen, when do you think the cutoff for "early" is? I am looking at a set of rears from a 95, so I wouldn't think that would be an issue would it? I will most likely get with you near the middle of next month for a set of plates I will obviously need.

cheers!!

//<86TA>\\ · 05-15-2007, 07:46 PM

looks good ed.

no parking brake?

ebmiller88 · 05-15-2007, 09:33 PM

Yes it has an e-brake. It attaches directly to the caliper just as it normally does on PBR discs, only thing different here is the backing plate. I just didn't get a shot of it.

Ed

Cadillac · 05-15-2007, 09:49 PM

Can we assume you sell the parts for this conversion?

Loving the brakes over here in Cali, Ed. Thanks!~

I've been looking for a limited slip diff with discs but appear to have stalled this upgrade until next year. I still want the braking power though.

What would this conversion cost?

ebmiller88 · 05-16-2007, 04:18 AM

Yes, I'll offer all parts for this swap...you provide the rearend. This is a great option for those who have the posi and gears they want but don't have discs yet.

Ed

Cadillac · 05-17-2007, 09:34 PM

I almost pulled the trigger on a 3.23 posi a couple weeks ago but ended up needing repairs for the little gal's car. I regret missing that chance and it didn't come with brakes.

Rest assured I'll be contacting you for this if it ends up I can find another (I really would prefer a 3.42 I think).

Thanks Ed!

ebmiller88 · 05-18-2007, 01:44 PM

I hear ya..my family has had two car appearance changes THIS WEEK, on two cars to boot.

If you could get a smoking deal on a 3.23 or 3.42 with drums, this would be the hookup.

Ed

rce2win · 05-18-2007, 02:27 PM

I'll be in for this mod at some point in the future. Thinking i need to get the car moving forward on its own power before i put a bunch of money into making it stop.

Matt_91RSTPI · 05-26-2007, 07:36 PM

I look forward to the release of the bracket and conversion kit. I've always wanted rear disk brakes, but didn't want to lose my Auburn Pro and 3.73s.

Brisk · 05-27-2007, 07:09 PM

so stock is 11.6" rotors, what is the part number for 12" rotors, or the two piece 13" ones?

ebmiller88 · 06-17-2007, 08:21 PM

The 12" rotors will be Baer units, the 13"s will be from a vendor I'm working with and I don't have the number or price on those.

Ed

ebmiller88 · 07-02-2007, 07:30 PM

Here's the followup to the comment I made about a different rotor that can be used which will take care of having to turn down the axle flanges to get it to seat flush against the rotor flange. Take a look at the pics below. The rotor on the axle is from a 1995 or so camaro/Firebird and is just slightly larger on the rotor ID so that the rotor will sit flat on the axle flange. No machine work required.

The zinc washed rotor with the tapered hat area would require the axles to be worked in this application.

Ed

catc · 07-19-2007, 12:19 PM

Could this caliper bracket be cut and drilled to work on a 9-bolt that has the cast iron calipers?

ebmiller88 · 07-20-2007, 10:34 AM

No need..I have new 9 and 10 bolt backing plates already made for you, they're at the plater and am leaving shortly to pick them up. I'll post up pics later.

Ed

Jeffrey Fontaine · 07-20-2007, 12:26 PM

This is great!

Plus, good for Monte Carlo guys

I think this will be the perfect match when I finally get off my duff and get the parts for the LS1 front brake swap!!!

catc · 07-20-2007, 05:36 PM

Hey Ed please put me down for a set of the 9-bolt brackets. I can purchase as soon as you let me know, maybe e-mail or pm. Thanks

dennisbernal91z · 07-21-2007, 07:34 AM

I really need a set of these! Is there a # I can call? Or is this all done over e-mail?

toms84ss · 07-21-2007, 08:58 AM

Ed, I will buy a set as soon as you have them available.

robertfrank · 07-21-2007, 10:30 AM

If I don't find me a set of aluminum drums I'll be all over this as well.

ebmiller88 · 07-22-2007, 10:03 PM

I currently have 5 pair of these brackets on hand. They will come with mounting bolts and instructions as well. If you need them (Dennis and Tom), please send PMs or e-mail and I'll get to you as soon as possible.

Thanks as always for the patience.

Ed

toms84ss · 07-22-2007, 10:27 PM

PM sent.

Lonnie P · 07-22-2007, 10:35 PM

Ed,
Please send me a phone # so I can contact you.

Trying to do a 13" front & LT1 or Ls1 rears.

my e-mail is sales@lonniesperformance.com

Thanks,
Lonnie

Black is Best · 07-24-2007, 06:20 PM

PM sent

ebmiller88 · 07-25-2007, 08:51 PM

Replying to PMs.

Ed

Iroczracer · 07-31-2007, 10:00 PM

Some time ago I posted trying to do the same thing!! Every body asked why I would want to do that... Not trying to bash on your brackets, they look great. The large bolt the top is not really needed, and can be squared at the axle flange. The top of the flange can be squared off to match. Bottom two bolts that hold the backing plate on, can be re drilled. Drill two holes in the top portion of the flange to complete. Last year I ordered two Chevy 10/12 flanges for patterns. This is how my 93 rear disk are installed on my 89 IROC. I had a donor car so everything is there, even cut the park brake cable holder off the floorboard with a spot weld cutter.

Just an idea...

ebmiller88 · 08-01-2007, 12:39 AM

No offense taken, but the plus here is that there is NO drilling or mods of any kind needed. The trimming of the axle flange was due to the curve on the back of the factory 9/10 bolt plates. Sure there's other ways to go about installing discs on a drum rear but this is the easiest solution. Mods can be done without ripping apart or destroying the factory design.

Another point to note, the center hole on a drum rear is different size than that on a disc rear, drums have smaller axle ends than the disc rears do. Installing a disc plate on the drum rear involves time and effort to center the plate exactly right. This is not needed with my plates, bolt on and go. A few members have ordered these plates and hopefully they'll post up when they're done with the install.

Ed

83MonteSS · 10-01-2007, 01:29 AM

How do we go about purchasing these brackets? Im ready to get started on my Monte SS.

ebmiller88 · 10-02-2007, 04:07 PM

PM me or vice versa..

Ed

Cadillac · 10-03-2007, 08:57 PM

Hey Ed... just wanted to follow up and say I found that 9 bolt 3.27 with disks. 250 bucks! I can't wait to install it along with a new MC with prop valve and speedo gear.

Kevman · 10-04-2007, 06:01 AM

This winter I have to redo my brake lines and all that stuff, about how much would this whole kit set me back? I mean the rotors, caliper, proportioning valve, backing plate, all that good stuff. Thanks, KP.

ebmiller88 · 10-04-2007, 08:38 PM

Quote:

Originally Posted by Kevman

This winter I have to redo my brake lines and all that stuff, about how much would this whole kit set me back? I mean the rotors, caliper, proportioning valve, backing plate, all that good stuff. Thanks, KP.

Sending PM with info.

Ed

Jetmeck · 10-21-2007, 01:53 AM

So the stock drum parking brake cable is used with this kit ?

ebmiller88 · 10-21-2007, 03:53 AM

Quote:

So the stock drum parking brake cable is used with this kit ?

No, you'd need disc cables. I can supply them as well as the other parts in the setup.

Ed

hardroc · 11-04-2007, 08:44 AM

hello.. was readin da post and i am interested in keepin my 9 bolt disks and swapping to a 10 bolt rear ... is that possible wit yur plates ? i also have a lt1 complete rear and wonder if those brakes would be better for useing our plates ... and what is your cost on this upgrade

KrisW · 11-04-2007, 09:39 AM

Ed, please PM me with cost info. I am interested in this swap as well.

Thanks!

ebmiller88 · 11-04-2007, 08:18 PM

Quote:

Originally Posted by hardroc

hello.. was readin da post and i am interested in keepin my 9 bolt disks and swapping to a 10 bolt rear ... is that possible wit yur plates ? i also have a lt1 complete rear and wonder if those brakes would be better for useing our plates ... and what is your cost on this upgrade

If I understand that, yes this will put PBRs from your 9 bolt onto your new 10 bolt.

Ed
----------

Quote:

Originally Posted by KrisW

Ed, please PM me with cost info. I am interested in this swap as well.

Thanks!

PM sent.

Ed

2badcams · 11-28-2007, 09:30 PM

Please send cost info gjaime@marinaco.com

watajob · 12-31-2007, 04:38 AM

Ed:
Please check your PM's.
Thanks!

ebmiller88 · 01-04-2008, 08:47 AM

Will do.

Ed

85camarojunkie · 01-06-2008, 02:52 AM

Been trying to get ahold of you for a while, I deffinetly want your brackets can you pm price and how long it will take to get them or send email to k.reed19@insightbb.com. Tired of searching for 9-bolt parts they officially suck. Please contact me. Thanks Kevin

chevyracingrox · 01-06-2008, 10:40 AM

don't you need to fill more brake fluid in the resivoir or get a 4 wheel disk master cylinder to get this to work though? i heard that disk brakes move more fluid than drum brakes. just wondering, because i'm tempting myself with this upgrade.

85camarojunkie · 01-06-2008, 12:03 PM

No not actually. You do need a proportioning valve, you can put that were you want. Your front disc brakes are running 2lbs of pressure were as your drums are running 10lbs. you can find a good one for around $32 or get one from a junk yard car for 10 bucks. This will keep you from having the nose dive effect, and blowing the seals from your new upgrade.

robertfrank · 01-18-2008, 08:21 PM

what would be the weight differance between this set-up and the regular drum rears?

greg320 · 01-20-2008, 04:12 PM

Ed,
Please check your PMs.

Would like to buy brackets and most of the rear brake setup for my 1992 RS drum to disc.

Thanks,

Greg

KJZ28/TA · 02-14-2008, 09:19 PM

Ed,

Please check your PMs I need to make semi-quick decisions. My brake lines finally went due to severe rust. Was about to buy the lines from Inline when I remembered reading your thread. I would like to buy everything possible for the drum to disc conversion if the price is right.

need to know before I buy brake lines what I am doing.

THANKS A LOT!!!

Cheers,
Kevin

Edit: I would also like to get Steel braided lines for the car from Summit...Does it make a difference if I get the Earl's 4 wheel disc ones or the disc/drum lines????

ebmiller88 · 02-15-2008, 07:01 AM

Kevin, I'll reply shortly. As for the lines, I include them in all my kits but if you buy, get lines for a 4 wheel disc car as that's the 5 piece line set.

Ed

maccladehup · 02-19-2008, 12:50 PM

this is what i have a 91 rs disc/drum and a complete 94 z28 (whole car) what all do i need to do rear drum to disc and maybe upgrade front discs im thinking about swapping most of the 94 car in to my 91 rs interior,engine,brakes,not the whole rear end i dont like the wider rear end. also arent 3rd and 4th gen lug patterns diffrent?

I H8 WWD · 02-19-2008, 03:59 PM

Is there an actual rear disc brake conversion kit, something made by a company or sold as a kit?

Or is this the only way i can get discs on my drum rear? I have searched and searched for conversion kits and cant find anything.

ebmiller88 · 02-20-2008, 04:24 AM

Quote:

Originally Posted by maccladehup

this is what i have a 91 rs disc/drum and a complete 94 z28 (whole car) what all do i need to do rear drum to disc and maybe upgrade front discs im thinking about swapping most of the 94 car in to my 91 rs interior,engine,brakes,not the whole rear end i dont like the wider rear end. also arent 3rd and 4th gen lug patterns diffrent?

My drum plates and the brakes from the '94. You'll also need correct e-brake cables and I'd install new axle hard lines and flex lines while you have it all apart. I can assemble a package for you if you'd like. The f body bolt patterns are the same.

Ed
----------

Quote:

Originally Posted by I H8 WWD

Is there an actual rear disc brake conversion kit, something made by a company or sold as a kit?

Or is this the only way i can get discs on my drum rear? I have searched and searched for conversion kits and cant find anything.

Full kits are no problems either, I can go from stock 11.6" to a full 13" rear rotor if you'd like. Price out a full kit from Baer and then get with me, I'll save you a lot of money.

Ed