GMT900 style caliper / PBR 15 square body question

[87chevy.com]

Several companies make kits that use these calipers but I'm looking for measutements... anyone have a caliper or these measurements handy?

The bolt spacing for the 2 caliper bracket bolts to spindle/knuckle?
The spacing from that to the center of the rotor?

Thanks
Clint

[LH Lead-Foot]

GMT800 from 99 - 2006? 2007 - up = GMT900?

I have caliper off of a 2003 Tahoe front & rear, but this falls into the GTM800 utility category. What year did the GMT900 start?

Retired ASE Master Tech, but have GM eSI up to 2004 only.

[87chevy.com]

Originally Posted by LH Lead-Foot

GMT800 from 99 - 2006? 2007 - up = GMT900?

I have caliper off of a 2003 Tahoe front & rear, but this falls into the GTM800 utility category. What year did the GMT900 start?

Retired ASE Master Tech, but have GM eSI up to 2004 only.

Think it was 08... they had a larger front rotor.
I think I found a combination of oe parts to build a big brake kit for the wilwood c10 pro spindle.

I wasn't able to delete this thread so I guess its here to stay lol..

Thanks for the reply though

[LH Lead-Foot]

As a ASE Master Tech since 1978, retired due to injuries, arthritis, and way too many lumbar fusions, followed by burning. Knees started this year and only 60.

Willwood is good stuff but about 6 months of my pay now. I have worked on 69 vehicles with 4 piston calipers, but were 4 cylinders. After years of imports, I ended up a Isuzu / GM tech. But work on Honda one day, Deloreon the next, then Lancia-Bata & Mercede's.

I had years of 2k take home checks per week after 95 hours plus Saturday in the shop/dealer to flag up to 114 hours +, working until 9PM at night. I can't remember how many times my wife brought dinner to work....Hey! That's what caused it, all of that work! Now I know why I hurt soooo bad.

Best of luck with your project. Truly wish you the best!

[68c10airstream]

Hi Clint, a project of mine in the future is using v8 dodge durango 4x4 (2014 i own) rotors and calipers. Rotor is 13.75" and lug pattern is 5 on 5. 18" wheels from my 68c10 restomod i bolted on my 2014 durango and just cleared the caliper.

I'm going to take my 72 1 1/4" thick rotors and machine them down to be the hub for the durango rotor.

[68c10airstream]

Hey lh-lead foot, I thought i burned the candle at both ends, going back after the kids are in bed, taking customer cars home for extended diagnosis time, swapping engines after work, etc, etc, but i've met my match.

I'm 61 and crappy back from an accident my boss did to me when 19 years old. Shift work at a power plant for the last 17 years working. Still love working on things, and just can't give up doing brake work. I feel your pain!!

Knees bothering you?? Me too, until my doc said "don't kneel without a soft pad underneath the knee". Until i started using the pad i couldn't get a good night sleep. X'ray, etc all good.

[LH Lead-Foot]

68C10airstream. I was moving rocks away from the wheat drill at 7. Ran cross-country and track in high school (7K mile club) & cross-country only in college, 5-6 mile courses 5 minute miles, got state mile record for 2A school 4:10. Yeh, knees hurting bad this year and getting worse every month. A boss pulled me off a starter rebuild to run a jumping-jack earth computer in mud for 5 hrs at age 28, pulled all muscles in low back felt like bad sun burn, had 5 surgeries with 4 fusions and now on fire from side to side. We tried radio frequency nerve oblation but didn't work. Fire still there. This project is my daily driver so want to it right once. I am luck to sew interior leather, vinyl with commercial Juki lock-stitch that has Alum. oil pan If you make patterns from cheap vinyl upside down, mark & cut exactly, the rest is up to your machine skills. I put a shaft and pulley system to reduce speed as it ran like a weed eater on WOT. Elbows shot, pinched nerves the one bad arthritic finger. Other wise fine. I have a 33 yr. old son who can help, but doesn't learn technical well like electrical, but can help. It is like they say...
Getting old is hell, but it beat the alternative!
Just wish I could earn that pay check again..at least for a while. Pain sucks!!
Got wheels yesterday and tires next month. Best of luck with your project.

[87chevy.com]

Originally Posted by 68c10airstream

Hi Clint, a project of mine in the future is using v8 dodge durango 4x4 (2014 i own) rotors and calipers. Rotor is 13.75" and lug pattern is 5 on 5. 18" wheels from my 68c10 restomod i bolted on my 2014 durango and just cleared the caliper.

I'm going to take my 72 1 1/4" thick rotors and machine them down to be the hub for the durango rotor.

I'm gonna try and mock up their v6 version and see if it will clear the 17" wheels I have now. V6 ones are non directional, same as v8, same thickness as v8 and corvettes, but 13", same as corvettes. Gathering parts at the moment.

[68c10airstream]

Clint, post your results here or pm me as i would love to see your quality work!

[87chevy.com]

Damn wilwood caliper bolt spacing strikes again. C5/c6 backets not chance on 13"/330mm rotor or the 350mm from the bolt patter measurements provided. Got a chance to measure a v6 Durango with the 13"brakes... no way to make an adapter for the v6 bracket to work with the 13" rotor to possibly fit my damn 17" wheels. From the research I've done, v6 and v8 use the same caliper pistons.. dodge parts catalog online shows a regular and HD brake caliper with a R in front of the regular 13" and had Refurbished in the description.. sounds like refurbished is the only difference and why the R is in the part number.. and funny ha ha is the refurbished part number costs 100$ more ??? A parts counterman is not likely going to know the difference, they will understandably ask for the vin and provide a correct part. They do seem to use a different bracket just like the corvettes do to space them further away. Dodge offers a separate v6 and v8 brake pad. I say v6 as in regular, 330mm rotor and v8 as in 350mm rotor by the way... on rockautos website, it seems the only difference in pads may be thickness. Some brands say 330 or 350mm rotors.. so.. at the moment not excited to make this wilwood c-10 pro spindle work...
Cad drawing that I put together plotting the measurements say a v6 bracket, and v8 caliper.. which doesn't have an R, like the v6 (which may be the same caliper) and the 350 rotor will work just fine.
I say just fine as in a bracket that bolts to the wilwood spindle and the dodge caliper bolts to the adapter and the rotor pilot bore is machined to fit a Chevy hub...

The silverado caliper and bracket looks like it will fit like a champ (with an adapter of course).

Seems only option for these wilwood spindles for me is
Option 1: $$$ on new rims and tires if it doesn't clear the trims I have (since I have 17") and approx 450 on the 13.8" dodge brakes, machine work and adapters which will come maybe around the same $$ a the wilwood 14" kit ... not saying it's a comparable brake kit at all!, just comparing size...
Option 2: $$$ 12" wilwood kit brake kit to fit my 17's.. really not even considering it
Option 3: selling the spindle kit I just got...

Damn cross roads in a project
Clint

[68c10airstream]

I was liking the wilwood pro spindle with a removable steering arm. Coleman racing lists many arms so i could dial in bumpsteer. Or machine my stock rotors down and deal with the stock bumpsteer situation. Jeep products run a 5 on 5 pattern also. And the dodge srt8 brakes should be top of the line as in a durango srt8.

[87chevy.com]

Originally Posted by 68c10airstream

I was liking the wilwood pro spindle with a removable steering arm. Coleman racing lists many arms so i could dial in bumpsteer. Or machine my stock rotors down and deal with the stock bumpsteer situation. Jeep products run a 5 on 5 pattern also. And the dodge srt8 brakes should be top of the line as in a durango srt8.

None would bolt onto an adapter to a wilwood spindle from my measurements. Dodge catalog shows 1 steering knuckle for all Durangos.. I could be looking at it wrong too. If not the same boat, wouldn't be able to fit them on with the matching 380mm rotor..

[87chevy.com]

Well, all the items came in for a mock up, 12.9"x30mm 5 lug rotor, 2008+/GMT 900 caliper assembly with bracket.
I do need to pay attention to the location when ordering junkyard parts on ebay... caliper came from new New York.. pin seized in the bracket and broke off when trying to remove. Spent a good hour getting almost all of it out with various techniques. In the end, the price I paid was a core caliper anyway.

Haven't made a bracket yet to test fit the assembly in my 17" american racing torque lite
wheel, but this setup barely fits the wilwood spindle. It may need the caliper bracket clearanced a few hairs... but haven't made a bracket so may be no modification.







Next step is to make a MDF bracket with washers to center the caliper on the rotor and to test fit. If it fits, next step an aluminum prototype, or just do steel..

If it doesn't fit, mine as well do the bigger Dodger brakes 13.8" x 32mm rotors and matching calipers which would need the same kind of adapter bracket. I will say my measuring technique was damn near spot on with a harbor freight caliper and steel ruler.

Clint

[87chevy.com]

Phew, successfully successful in mockup! I have about 1/8 of room between the caliper and rim/wheel weights.







The square blocks are just a "washer" to take up some of the bolt length. Tractor supply only had 2" long bolts and didn't want shorten the bolts at this time. Used my hand held router to make the spacers to center the caliper bracket on the rotor out some scrap MDF.. cheaper than buying a ton of washers and can get the spacer to just about the right dimension to boot.
Plan on making the bracket out of 3/8 steel and have some spacers in steel made and call it done. Need to price out calipers and decide on what type of rotor I want, solid or maybe drilled.. rears are solid... not sure if I would want a mis matched look

[Mike C]

Excellent project. I’ll be following along.

[83GMCK2500]

Originally Posted by LH Lead-Foot

GMT800 from 99 - 2006? 2007 - up = GMT900?

I have caliper off of a 2003 Tahoe front & rear, but this falls into the GTM800 utility category. What year did the GMT900 start?

Retired ASE Master Tech, but have GM eSI up to 2004 only.

Came here because I like brake upgrade threads, and to confirm these dates. There are 2007 "Classic" trucks that are GMT-800 and then you will see trucks labeled 2007.5, those are GMT-900. For Duramax owners/shoppers 2007.5 marks the beginning of LMM engines first equipped with the DPF in the exhaust.

There's an overlap of GMT400/GMT800 in 1999-2000, an overlap of GMT800/GMT900 in 2007, and an overlap between GMT900/K2XX in 2014. Thanks GM.

[87chevy.com]

Nailed it

Stock



Somehow terrible shot of the knucle/spindle







Just need to order some brake lines (stock ones are too short) and that concludes the brake upgrade part of my project

Clint

[Goats86]

Clint, can you recap the exact parts you used for this as I have a new set of rotors and pads for a 2002 suburban and I can't find a home for them. I may as well use them if possible. Thanks

[87chevy.com]

Originally Posted by Goats86

Clint, can you recap the exact parts you used for this as I have a new set of rotors and pads for a 2002 suburban and I can't find a home for them. I may as well use them if possible. Thanks

Wilwood c-10 pro spindle drop spindle, stock Wilwood hub that comes in kit, custom brackets designed by me and sent out to a machine shop, 12.9" x 1" rotors from a jeep Cherokee w/ hubs enlarged to fit hub and 2018 Silverado calipers... same as 08+, not PBR brand , there Akebono brand.. i got lucky on an Ebay search and picked them up with 6 miles on them for a good price.... heck new wouldn't have broke the bank either..


Sounds expensive, slightly over 950$ and still need brake lines. But this leaves me the option to pick any rotor available for the application, cheap aftermarket stock, mid grade to quality aftermarket, factory, slotted, drilled, both... kits offered is one and done and not likely off the shelf available.

If I had larger rims, 18"+, which I dont, I would have used the later model Durango 350mm (13.8") x 32mm ( 1.25") rotor and matching caliper... this fills up my wheel just fine and should be a solid upgrade.

If my bud Aaron steps up to the wilwood spindles for his 68, hes running 20ish Intro rims, I'll draw them up and have them cut out and post up.. but nothing in the works.

[Goats86]

thanks for the info