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Discussion in 'The Garage' started by ldo_marlin, Oct 26, 2006.
Anyone have info on possible brake upgrades on a front D44? larger calipers, rotors ?
Other than 3/4 ton?
Yes other than 3/4T
Howe makes a direct replacement dual-piston caliper.
Ford outers will will get you dual piston too - but more parts to do it, and not as 15" wheel-friendly.
Hydroboost makes things a little grabbier.
Moving up to a 1-ton rotor.... its 1/4" thicker, so you need a caliper that can open that far. GM D60 caliper brackets are probably not very available. Maybe look at 88-97 F450, and 96-02ish E-450 cubevan. Both use 16" wheels. You'd need to fab or adapt the caliper bracket.
Here's the E450 setup:
More pistons or bigger bores gets you more clamping force, but it upsets the delicate balance of whole brake system leverage ratio. That being the ratio of the m/c bore to the caliper bore(s) multiplied by the pedal ratio and adding in the booster's boost. Rarely can you simply throw on some calipers with a larger piston area and not have other issues develop b/c of them.
H-Boost, being additive rather than multiplicative, doesn't upset the balance and can increase the brake's effectiveness.
The same is true of larger OD rotors. They don't upset the leverage ratio and will increase the leverage of the brakes. That increased leverage, with the same clamping force, will improve the brake's effectiveness. Rule of Thumb for maximum rotor OD is 2" smaller that the rim size. So the max rotor OD for a 15" rim is about 12"
Depending on the caliper you can go a little bit larger than the RoT, but this is extremely unlikely with a stock type caliper.
You got some funny math there, mister. I always thought that 15-2=13.
OD of the rim is 15", but inside is smaller... so what he's on about is rotor plus caliper must fit inside the rim. Ask me about my dually rims (which are >12") inside a 16" rim
Well, converting to rear disc has some balance implications too.
Considering the 1-ton and 3/4-ton masters are interchangable, and adjustable PVs are readily available, there's few different variables to mess with.
Anyone done the Howe dual piston calipers? Is it really bolt on?
My application is not K5 specifics but for a scout II project. I hope you guys don't mind me asking questions on this board. I don't own a K5 but my daily driver is a 85 K20 Burb
So here is the brake plan so far. Hydroboost. The rear is a D60 with Wilwood 4 piston alum. calipers, 12" rotor. The front is a GM D44. Ford rotor to keep the 5x5.5 pattern. GM calipers. I am looking to upgrade the front brake setup. If the Howe dual piston calipers are bolt on, May be that's the ticket. Lots of choices available for Chevy 2wd front setup but not much for 4wd.
Here's a build where somebody used the Howe calipers.
I thought the 2wd calipers were the same They look very similar. I should check the 1/2-ton 2wd calipers I have to see if they fit the 4x4 bracket.
I was just thinking about 2wd possibly fitting 4wd. Different part #s probably due to different piston sizes. Pls. let me know what you find on 2wd caliper fitting a 4wd setup. I'll try to stop in a parts store tomorrow to compare.
What the largest piston size that's available stock?
I can't get to my tools and half my parts tonight
The 2wd 1/2ton stuff is all together still, but the pin to pin measurement is just a hair over 7". Form a couple searches, that jives with the basic GM D52 caliper. The hose fitting seems to be located a little different - probably because its 2wd.
I can't seem to fin the stock piston sizes though.
Searching partsamerica.com i find 2 15/16" and 3 5/32" pistons. Probably more sizes depending on 1/2T or 3/4T. Partsamerica has a "see all vehicle this product fits" button. Some part# were the same on 2wd and 4wd. From 79 and newer, there was a change in part#. Was that a change from GM D52 calipers to GM metric (D154)?
Howe has single piston D52 calipers but does not state if the double piston were D52 calipers. I'll call them Monday to get info. I hope their calipers are not 2 pc stuff because hydroboost will kill it.
The D154 isn't even a possibility. Its 1.5" smaller from pin to pin.
I had no idea the OE 3/4-ton piston size was that large. There may not be anything to gain with the Howe calipers.
Spoke to Howe. Their caliper is not bolt on but will work with "some modifications". Furthermore, the calipers will not mount as tight as factory because in racing appication, the caliper are designed to "float over the rotors" providing minimal brake drag.
Probably will try to use stock calipers with largest piston
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