This is for the 90-02 AWD models. I just replaced, my front calipers with 4wd 1 ton(or >8600 GVWR 3/4 ton) pickup units and the matching pads. Pads offer 10-15% more surface area and the calipers have larger pistons. If you speak "hydraulics" you'll know this equates to more pressure on the pads, for the same pedal effort. Stock disks work fine, but i suppose you could get them cross drilled, or slotted if you really felt the need. Make it real easy and buy 2 loaded calipers.
Doc
1998 3500 4x4 single rear wheels.
They are in and working fine. The only diffrence is the Piston is a tad larger. Pads are thicker width wise. Dont see why you couldnt just order the pads as the caliper case is the same size..just larger piston.
Upgrade brakes in.
If you find a BIG brake kit let me know as im always looking for better stopping power as i pull a big race trailer.
Piston internal is 69mm across and outside is 77.52mm
Pads messure 50mm x 121mm
Chartman
Well, I took the bait and tried it. I bought calipers and pads for a 92 K2500 8600 gvw. Bolted right in with no problems at all. I didn't plan on doing it so soon but I had to replace the brake lines and of course, the bleeders just snapped off when I tried to bleed them. Total cost with tax $71.65 US.
BTW, mine van is a 93.
AdvanceAutoParts numbers:
Cardone Lifetime caliper 184298
Cardone Lifetime caliper 184297
Silver wearever lifetime pads MKD370
I always buy the cheaper pads for my cars due to the hill I live on. They get used heavily and the good ones tend to eat up my rotors. Much easier\cheaper to replace the pads every year or two. They seem to work well but haven't driven much since I'm in the middle of a bunch of projects on the AWD.
Lockdoc
Just put them on today. GM pt.# 18035930 and 18035931. These are reconditioned and come loaded with pads and hardware. My cost as an employee was 102.00 including tax. There is a core charge if you don't return your old ones.
Still bedding the pads. The AC Delco #'s are 18R741 and 18R742
BigAt
Well, it's been a coupla weeks and the results are great so far. Stopping power on my truck is 100% better. Keep in mind that I also changed over to 11" drums at the same time. I can tell though, the fronts are definitely clamping down with more force than before.
I have an issue with an annoying pull to the left when braking. Was much worse initially, but it seems to be slowing fading away. At the same time, the brakes were getting better and better (I guess they needed a proper break-in period). Another factor may be the readjustment I made to the rear drums.
Another issue I have is with front brake shudder. The rotors are only a year old, with less than 10,ooo miles on 'em. I had them turned just the same while doing the caliper swap so as to give the new, bigger pads a proper break-in surface. The shudder also seems less than before, but it's still there. So I've picked up a set of Powerslot rotors which I'll be mounting on ZZ this Saturday. I'm curious to see if the pull and/or shudder issues are resolved afterwards.
Peter
In fact yes, your observation is true that this would shift braking bias towards the front axle, proportionately based on the change in caliper piston cross-sectional area. BUT only if the front and rear hydraulic circuits were driven by one master cylinder circuit. However in reality it is not that simple. The master cylinder has two pistons mechanically joined providing fluid seperately to the front and rear circuits. enlarging the caliper pistons on the front circuit, also increases the required volume of fluid required to do the work, requiring more master cylinder stroke to supply that added volume, and increased pressure ratio. This means more stroke and volume applied to the rear circuit as well as the pistons for the two circuits are rigidly mechanically joined.
Whew... Now for the real world results.
Turns out this makes the rear brakes work harder(this time increasing pedal effort) and sooner too. They will wear faster, but as they often outlast 2-3 sets of front pads, this isn't a concern.
In fact if you were to put too large a caliper on the front the rear would lock before the front could really begin to work.
The astro/safari AWD calipers/pads are identical to similar year 1/2 ton and light 3/4 ton pickups. swapping 1 ton calipers/pads onto these is a common upgrade known by tens of thousands of professional mechanics. It's been done in dealerships. I just tried it on my Safari. My calipers cost 35$ each and they accepted the stock calipers as core returns. (They rebuild those too)
The next thing to try is 11 inch caprice police/taxi rear drum assemblys. Or disks, hmmm
DerSafariDoctor
). I'm hoping that Paul's comment of the rotors having straightened themselves out after retorquing applies here.
I have a AWD Safari and didn't even know it.... (free upgrade)