I did it! Stuffed duramax rear axle in my 94 suburban

[Petrella]

I got the big sucker in there, all the brake lines, e-brake lines all fitted perfectly, had to move the spring perches in 7/8" no big deal, and got my driveshaft shortened a couple inches. had to change the yoke and u joint, as it is bigger on the 11.5" the donor axle was out of a 2004 duramax, with only 5000 miles on it. the paint was still new! the rear disc brakes are awesome!!! the truck stops a million times better, must say im kinda glad i broke the old 10.5" with drums, hehehe.....
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1994 K2500 4x4 Suburban
6.5 Turbo Diesel
Pyro,Tranny,Oil,Diff temp Gauges, Boost Gauge
FSD Cooler from my GM dealer
Sweet sounding JK Exhaust
Heath Chip
Boost Controller
Crystal Projection headlights, Turn signals and reflectors.
Euro Tail Lights
Cowl Induction Hood
2" Lift
305/70R/16 BF Goodrich All Terrains
11.5" FF 3.73 Posi with Rear Disc brakes
American Eagle 16x10 chrome wheels, style 145
Alpine Stereo,DVD,Navigation System, and Alarm
Indigo Blue Metallic
Pics of my truck - http://www.picturetrail.com/gallery/...=anthony1982&x

[ 01-02-2006, 07:19 PM: Message edited by: Petrella ]

[john8662]

Article Material?

[Tough Guy]

What was the cost?

Chris

[1bad383]

How practical would just a brake swap be? I am seriously considering getting rid of the drums. Going from a '94 10.5 rear, second gen rear I think.

[DA BIG ONE]

Nice indeed!

How about a indepth evaluation on the braking?

I'd like to know if you needed an adjustable perportion valve, or does the drum brake unit work just fine?

[Petrella]

drove the truck to a skiing resort about 2 hrs away from home, heres what i found about the brakes:

brakes are stronger and truck stops better, but must push pedal down alot more, i dont know why?? im assuming that the pistons in the calipers in the rear, have more travel then the original pistons in the drum brakes, therefore the pedal goes down further then the drum brakes, i dont know how to shorten the the travel of the brake pedal but other than that there are no problems at all.

Total cost for the swap was $950 canadian and 5 hrs labor

[twaddle]

The caliper pistons will require more volume of oil to operate due to the larger diameter and possibly more pistons compared to the original cylinders on the brake shoe set up.

The only way to overcome this problem is to install a larger brake master cylinder.

Regards

Jim Twaddle
Biggar, Scotland

[JohnC]

OK, this is a little off topic, but is there any reason you know of why the wheels from a 10.5" FF axle won't fit on the 11.5 inch hubs?

[Petrella]

the wheels from my 10.5 full floater, bolted right on to my 11.5" with no problems.

as for the larger master cylinder and which one can i use????

[twaddle]

I'd look at the master cylinder off a Duramax vehicle to the spec your axle came from to start with.

I don't know if it would fit staight on but it's a start, compare mount flange, stud holes and pipe connections.

Out of curiosity how far down does the pedal go before the brakes bite and is it something you could get used to?

Regards

jim Twaddle
Biggar, Scotland

[More Power]

Bleed all the air out the brake lines? A bubble will cause a soft pedal.

Jim

[Petrella]

gotta push the pedal about half way down before the brakes bite, the do feel kind of spongy, but the brakes do grab good, i bled only the rear brakes, thinking that the front wouldnt get affected if i opened the brake line to the rear. would it make a difference if i bled the front?

Jim, would you know if a master cylinder off a duramax fit my sub??, also would the bigger master cylinder off the 6.5 duallies make a difference?

[ 01-04-2006, 02:00 PM: Message edited by: Petrella ]

[CareyWeber]

Originally posted by Petrella:
gotta push the pedal about half way down before the brakes bite, the do feel kind of spongy, but the brakes do grab good, i bled only the rear brakes, thinking that the front wouldnt get affected if i opened the brake line to the rear. would it make a difference if i bled the front?

Jim, would you know if a master cylinder off a duramax fit my sub??, also would the bigger master cylinder off the 6.5 duallies make a difference?

Differences:
Hydro-boost disk brake the cylinder on the passenger side is blue (gold for drum)

Master cylinder disks take more volume.

Proportioning valve they are different between disk and drum units. Some people have run drum valves with disks.

Check valves disk brakes need to retain some psi (IIRC 2 psi for disks) this is what I think is your issue.

Carey

[More Power]

Petrella, I don't know if a master cyl off a 2500HD/3500 would work or not. Looks like it might, but...

The brake pedal feel and travel on Lil Red's rear disc single piston conversion is nearly identical to when drums were on the truck. I listened to all the info about 2 psi residual pressure and the need for a different proportioning valve. Turns out the discs work great without doing anything special.

I did install a new hydraulic brake booster and master cylinder made for a 1989 model year 6.2L diesel equipped K2500, and I'm using the factory Duramax PS pump. A new master cyl was installed cuz the vaccum brake master cylinder wouldn't fit the hydraulic brake booster without some machining.

Bleeding brakes is easy when using the right equipment. I'd try bleeding the rear brakes one more time. Start with the side having the longest line (farthest from the master cyl). Be careful not to run the reservoir dry.

Jim

[Petrella]

thank you for the reply, but would you know if the bigger master cylinder off a 6.5 dually with code H in the VIN actually make a differece?? if it does i can purchase one for a good price. (if i have A VOLUME ISSUE)

[More Power]

Chris replaced the original 2500 9.5" semi-floating rear axle in the K2500 6.5 Project truck using a 1999 3500 SRW 10.5" rear axle. The drums on the new axle were some larger than what were on the original axle. He used the same master cyl. No problems...

That said, I'd bet the 3500 dually master cyl would bolt right onto your truck...

Jim

[david]

No one has said any thing about the proper way to bleed the brakes!!!!!!!!!!!
Some time back they changed the way they run the lines.
Old style, the front wheels were connected to one resavoir and the back to the other one.

NOW the left front and right rear are connected
and the right front and left rear are connected.

So you must blead them that way or you will never get the air out!!!!!!
Hope this helps!!
David

[Petrella]

David, i hope yur right! cause i never tried bleeding the front brakes yet,i dont know what you said is possible because there is one brake line that runs to the back of the truck then splits at the diff for both calipers, i cant see it work how you said. if the lines are connected like you said on my suburban then i definately have air in the system

[Petrella]

PROBLEM SOLVED, read in the chilton manual that the pressure pin on the proportioning valve MUST be pushed in when bleeding the brakes. So i pushed the pin in and held it, bled all 4 calipers and voila brakes are beautiful!!! no more pedal down to the floor to stop, feels like normal except you really feel the truck stop better now and you hardly have to push the pedal to bring the truck to a complete stop, so ive learned that as long as the brakes are bled properly no modifications have to be done to the braking system!

CASE CLOSED LOL!!