Rear disc conversion

[Truenorth]

Has anyone done a rear disc conversion for a Sierra 1500. I believe my truck is 10 bolt semi-floating axle( I'll have to confirm that some how with out taking off the diff cover). Does chev have bolt on parts for this conversion since most late model trucks nowhave discs?

[a5150nut]

Checked into doing my k2500. Late model brakes are a new design and won't fit. They use internal shoes for a parking brake.

There are several places that offer kits for the 1500. Try looking in 4x4 mags or do a search in Google or Lycos. The ones I saw used front rotors on the rear with Cadilac calipers and their own backing plates burned from flat steel.

Or you can order a Dana rear with any brake configuration you want. Starting about $1500.

Hope that wasn't too much COLD water at one time.... :eek:

[tanker]

Member Ron Pierce from Wyoming has changed his 1500 pick-up to rear disc brakes, tows an Airstream to "The Diesel Page" Rendezvous' each year. smile.gif

[cruzer]

Check out pirate4x4.com I know they have brackets
and tell you what parts you need for the 14bolt FF. I think it uses GM parts for the conversion.
Maybe they have something for a small rearend.

[grape]

www.coloradok5.com (http://www.coloradok5.com) they did a conversion on that site that has rotors, studs, and brackets with no calipers (78 caddy) for $185. The pair of calipers is about $100 from my local auto parts store and they hook up to the factory parking brake cables.

[Truenorth]

Thansk for the great info, I'll look into it.

[Ralph Fichtl]

Here is another one.

http://www.tsmmfg.com/

[Truenorth]

Does anyone know where I can confirm my rear axle(full floating or semi). I called the local chev deal and he said I would have to bring the truck in to confirm what it was . I'm pretty sure it is a 14 bolt semi floating, since the truck is a 1500.

[john8662]

You will have to look at the axle to make sure. First off, how many wheel lugs? 6 wheel lugs, then it is a 10 bolt. If you have 8 wheel lugs then you have a semi or full floater 14 bolt axle. use this page for identifying by the pan which axle you have (mainly for the 14 bolts, full or semi)

http://katy.tx4wd.org/tech/axle_id.htm

[Gapper_ca]

Before you decide to make the change to a rear disc. just how much driving do yo do off the pavement? i had a 2000 chev with the rear disc, and i had to replace the rear brakes at 40,000 kms. i drive about 75% of the time on the gravel roads here (they are much smoother then the hwys). i now have a 96 gmc with rear drums and have over 220,000km on it with no problems with rear brakes. gm does make a rock guard for new trucks but it is very $$$ to run the new rear disc brakes on a truck.

[Peter J. Bierman]

I ordered a conversion kit for a 85 blazer a few weeks ago from azkickin.com.
$185.- plus $100.- a piece for loaded callipers at the local parts store.

Have the stuff not in jet so can't tell you about installing. This is the kit the colorado K5 boys reffer to,( the product is now made by a different company named AZkickin )
In the article it looked simple enough to try.

Peter

[GMCfourX4]

I did a 14-bolt FF disc conversion on my truck using TSM's kit and the Caddy calipers. I still haven't figured out the best way to have the e-brake work, but the disc brakes themselves work fine. I still have to figure out how to change the proportioning and remove the residual pressure valve w/out messing up the ABS.

TSM does make a kit for your truck, I believe. In the case of my truck, getting the rotors from them was much cheaper, and I SHOULD have gotten the braided stainless lines (piecing them together cost more money, and way more aggravation). For the rest of the lines, I got a Russell? kit from Summit, and now I have all braided stainless. I managed to find the calipers locally for less money. The guy I talked to when I called there was very pleasant, and very helpful.

-Chris

[G. Gearloose]

Originally posted by john8662:
You will have to look at the axle to make sure. First off, how many wheel lugs? 6 wheel lugs, then it is a 10 bolt. That is not a accurate rule.

Some years the 14 bolt semi-floater was placed on K1500 series trucks.

[MJEasly]

I have looked into the idea of converting my K2500 14FF rear drums to disc. I am not happy with constant maintenance required to keep the front pads from being chewed up and the performance of the rear drums, when adjusted properly, is only marginal at best. The cost to replace the drums is also about the same as a complete rear disc setup, so when my drums reach the end of their service life, I'll be upgrading.

A couple of things I have discovered during my research:
-Caddy Eldorado rear calipers from 77-79 seems to be the e-brake caliper of choice. There is an unusual parking brake adjustment procedure requiring special tools IIRC. Make sure to ask about this adjustment procedure before you buy. Also, a lot of people I talked to say the parking brake mechanism will not hold a 1-ton or 3/4 ton application as the clamping force is not sufficient. You will have to decide if you want to take that risk if you are towing, etc...
-There is another e-brake caliper available for the 14FF application. TSW has it listed as a "Large GM" caliper that carries a GM OEM part number. Good luck finding out from which application they sourced the part, because TSW will not say. The only difference I can see is the larger piston. The parking brake mechanism may have a larger clamping force for those that tow, but do not know for sure.
-I have talked to a number of kit manufacturers and they mostly say the stock master cylinder and ABS system will work just fine with the rear disc setup. I would look into removing the residual valve from the stock master cylinder if you go this route.
-On the other hand, I would prefer to use a master cylinder that was a closer match for the F/R disc setup. I found this (http://www.napaonline.com/cgi-bin/ncommerce3/ExecMacro/NAPAonline/search_results_product_detail.d2w/report?prrfnbr=15515581&prmenbr=5806&usrcommgrpid=43448126) master cylinder from NAPA. It is sourced from a P-30 diesel step van with front and rear disc brakes. It also has a larger front circuit bore which should help overall front brake performance. The other plus is that it is from a diesel, which means it should bolt right up to the hydro-boost system without a problem.
-AZKickin offers a SS hose kit for the caddy caliper. It has all of the fittings and seems to be reasonably priced. It sure beats running all over town trying to find the proper fittings.
-A rear wheel spacer will be needed if your rear brake drum slides off of the axle. If your drum is pressed into the hub with studs, then a spacer should not be required. I will get a spacer that corrects for both drum brake thickness and the narrow track in which we currently enjoy.
-Go with stock 3/4 ton disc brakes from a late 70's GM truck. Most auto stores will have them at a somewhat reasonable price.

Granted, most of this is for the 14FF, but may help those with 1500 conversions as well.
-

[ 10-08-2003, 05:35 PM: Message edited by: MJEasly ]

[GMCfourX4]

MJEasly;
Thanks for the heads up on the master cylinder...but it got me thinking. I found THIS (http://www.napaonline.com/cgi-bin/ncommerce3/ExecMacro/NAPAonline/search_results_product_detail.d2w/report?prrfnbr=15515873&prmenbr=5806&usrcommgrpid=59785144) master cylinder for a C3500HD/4-wheel disc diesel truck, which has a 40mm bore, and the same threads (supposedly) as my factory master cylinder. This is almost 33% larger bore, and it looks like a bigger brake fluid reservoir as well. Might have to get one of these....

-Chris

[MJEasly]

CMCfourX4,

I found these NAPA parts during my research:
TSM101688 - 34mm bore
TSM101873 - 40mm bore
TSM101695 - 28.58mm (1.125) bore

I think the stock master cylinder bore for the K2500 (at least the 99) is 28.58mm IIRC.

A larger bore will move more volume and give you a harder pedal. You can go too large on the bore size. See this link (http://www.wilwood.com/faq.asp#question20) for more information.

I think there is a master cylinder sizing formula that gives the best compromise between pedal hardness and braking power somewhere on that site. The question I have is can we go with a slightly larger master cylinder bore and get more volume to the front calipers while maintaining a reasonable pedal feel since we are using the hydro-boost unit?

So, if you get the 40, please let me know how it goes!

[ 10-09-2003, 08:15 AM: Message edited by: MJEasly ]

[GMCfourX4]

I'm thinking with the hydroboost and more volume, there shouldn't be too much of an increase in pedal effort. The 40mm MC I found is for a 3500HD w/the 6.5 and 4-wheel discs.... I would think they would have set it up to have a "normal" amount of pedal pressure, but the increased bore could be due to having a larger volume to fill at the other end (a caliper piston requires a lot more volume to move than a wheel cylinder). Keep in mind, too, that the 3500HD is rated at (I think) 15,000 GVW, so it should be able to stop quite a bit... I'll let you know what I find out, but it could be a while, this weekend is my cooling system/intercooler project :D

-Chris