Best street pads for D52 calipers???

I'm running the Wilwood version of the D52 caliper front and rear on my '72 C20 Suburban. They system is sorted and works well, but I can't find a good pad for the street. I've tried the BP-10 and BP-20 pads....neither provides the initial bite, or overall stopping power I'm looking for with a 3/4 ton truck.

I then tried the Wilwood E-compound pads....those are exactly what I was looking for as far as initial bite, pedal feel, and overall stopping power. The problem is the only thing worse than the excessive brake dust is the incessant squealing...essentially turned my truck into a city bus. Both would be acceptable on a track car, but this is a daily driver. The dust is so bad that my white letter tires are black after 1 day of commuting to and from work. The squealing is unbearable in a daily driver....its constant and consistent.

So does anyone have a pad recommendation? I'm back to the BP-10s for now, and while they're quiet and low dust, the pedal effort required to stop the truck is excessive.

Thanks for the help!

I had to look up what the D52 was. For one, as you mentioned, you're trying to stop a 3/4 Ton vehicle with a 4 piston brake. Have you considered stepping up to a 6 piston? Two, if you can't for some reason, perhaps adjusting the geometry of the brake pedal to the master cylinder might provide more braking ability from your current caliper? Third, it looks like you've done a lot of experimenting with pads so maybe see what Wilwood recommends?

I assume you're running manual brakes? If you add a vacuum booster you can run whatever street pads you want and not have any pedal force issues.

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Originally Posted by Tsaints1115

I had to look up what the D52 was. For one, as you mentioned, you're trying to stop a 3/4 Ton vehicle with a 4 piston brake. Have you considered stepping up to a 6 piston? Two, if you can't for some reason, perhaps adjusting the geometry of the brake pedal to the master cylinder might provide more braking ability from your current caliper? Third, it looks like you've done a lot of experimenting with pads so maybe see what Wilwood recommends?

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I don't think the number of pistons is the issue. The D52 caliper was factory equipment on most GM cars of the period with front disc brakes. These just happen to be the Wilwood version so the caliper is aluminum as opposed to steel. Additionally, my options for brake kits are limited as this is an 8 lug truck.

I've done all the geometry and math associated with the correct pedal ratio and booster size to ensure this system is providing enough force to the system to adequately squeeze the pads, so I don't think thats the issue at this point.

As far as Wilwood goes, I've tried all 3 of the pads they offer for this caliper. Because its a fairly common caliper, there are lots of other manufacturers that make pads that will fit, Im just hopping someone has some experience as the trial and error method is getting expensive. It really is interesting to me the drastic difference between driving the E-compound and BP-10 pads back to back...the initial bite on the E-compounds is impressive, just not livable on the street.

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Originally Posted by stab6902

I assume you're running manual brakes? If you add a vacuum booster you can run whatever street pads you want and not have any pedal force issues.

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Nope, 11 inch, dual diaphragm booster

Hmm, you shouldn't be having any issues then. Are you sure the booster is working correctly? What pressure are you seeing at the calipers with "acceptable" pedal force?
There are millions of trucks running around with that size booster and the cheapest AutoZone pads with no issues.

Brand new booster as the original set up was disc/drums and had a single diaphragm booster which wasn't providing enough boost. I went to the '73 and later 11 inch dual diaphragm for the disc/disc trucks. Ill have to pull a wheel off and put the pressure gauge on one of the front calipers this afternoon and let you know what I come up with.

A cheap option I’ve seen people recommend is police/taxi option pads from mid 90’s Chevy Caprice. They have a bigger pad area.

For my D52 setup, I went with Hawk HP+ compound. Kore3 supplied mine. They mainly sell Corvette swap brake kits but if you call in, Tobin can set up a proper D52 brake system for you.

Most people would describe the average square body truck as having over-assisted brakes, even with cheap parts store replacement parts, so something isn't adding up. You said you ran all the numbers already, so I'll trust you're pretty close to a factory truck or full sized rwd car running those calipers. Your vacuum level at the booster is good too?

One more obscure thing to check - are you running true vacuum hose to the booster? Some people mistakenly run fuel hose, which can collapse, especially when it gets hot under the hood.

also confirm you have a disc/disc proportioning valve, had a buddy go through this recently, Brakes would stop the truck but could not do an emergency type stop.

Oh man!.....I feel REAL dumb! My pedal ratio is in the neighborhood of 6.75:1....great for manual brake car, terrible for power brakes. I think I confused myself as I've been going back and forth working on my '64 Corvette with manual brakes and the '72 Suburban with power brakes. The power brake hole is about an inch lower on the pedal...I just need to enlarge it a bit to fit the pin I'm currently using. That should put it in the 4.5:1 range which should be just right.

Again, I feel REAL dumb....

I agree that you should use the power brake hole to get the geometry of the input rod correct (roughly straight into the booster), but changing the pedal ratio from 6.75:1 to 4.5:1 will increase pedal effort and decrease pedal travel, all other things being equal. Was your original problem excessive effort or excessive travel? It's a balancing act between the two.

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Originally Posted by stab6902

I agree that you should use the power brake hole to get the geometry of the input rod correct (roughly straight into the booster), but changing the pedal ratio from 6.75:1 to 4.5:1 will increase pedal effort and decrease pedal travel, all other things being equal. Was your original problem excessive effort or excessive travel? It's a balancing act between the two.

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Yes, in addition to the lack of bite, pedal travel was a bit on the excessive side, and effort was very soft. I think going to the shorter hole will fix all of the issues.

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Originally Posted by FLYNAVY53

Yes, in addition to the lack of bite, pedal travel was a bit on the excessive side, and effort was very soft. I think going to the shorter hole will fix all of the issues.

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Gotcha - glad you got it figured out!

I appreciate all the input....I've been chasing this for a while now, and the whole time, it was right in front of my face!

I have seen this scenario before and would like to point out that Wilwood produces D52 style calipers with two different piston sizes. The mistake many make is to install the small piston calipers on the front, then driving themselves nuts wondering why the vehicle wont stop.

Here are the front calipers in black:

https://www.summitracing.com/parts/wil-140-11291-bk

Notice the piston sizing of 2" (that's two pistons each being 2")

Here are the rear calipers in black:

https://www.summitracing.com/parts/wil-140-11293-bk

Notice the piston sizes of 1.250" (that's two pistons each being 1.120")

I can't tell you how many times I have run across customers that have accidentally put the small piston calipers (meant for rear brake use) in the front. They can't stop, trying everything, then contact me where I ask them to chase down the P/N ordered to find that they have accidentally put the rear spec calipers onto the front. Swap in the larger piston front spec calipers and all is well.

Double check which calipers you have installed - correct if / as needed.

:cheers:

Thanks Paul, I definitely have the right calipers on the front and rear.

I got the pedal ratio sorted out to night, and the truck stops 100% better....still feel like an idiot, but it happens I guess. Pedal travel is short, and significantly firmer, but it stops really well. I still like the initial bite of those e-compound pads, but like I said, the noise and dust was a deal breaker on the street.

Ill probably still give Tobin a shout to see what he recommends as far as pads go in a truck this heavy. Thanks for all the assistance!