Dual piston brake caliper swap?

[SteveSRT8]

if he's throwing out the parts in question this may affect the problem, eh?

 

[Stu_Rock]

Craig--Regarding the uneven pad wear, I would say both outboard pads were somewhere around 10%-15%. The wear was a little uneven on each caliper, but it was perfectly symmetric on the car. Some pad sets have different inboard/outboard friction material, so that's my suspicion here.

Steve--Regarding the caliper swap, the hydraulic volume is the same between the 1-piston and 2-piston designs (see earlier posts above). The big difference is the surface area of the new pads.

 

[Craig in Canada]

Originally Posted By: Stu_Rock
Craig--Regarding the uneven pad wear, I would say both outboard pads were somewhere around 10%-15%. The wear was a little uneven on each caliper, but it was perfectly symmetric on the car. Some pad sets have different inboard/outboard friction material, so that's my suspicion here.


K, never mind then...

Quote:

Steve--Regarding the caliper swap, the hydraulic volume is the same between the 1-piston and 2-piston designs (see earlier posts above). The big difference is the surface area of the new pads.


Generally (i.e. depending on a whole lotta things) the thing I like most about multi-piston calipers is the feel, pedal response and ability to modulate the braking.

 

[Stu_Rock]

Originally Posted By: Craig in Canada
Generally (i.e. depending on a whole lotta things) the thing I like most about multi-piston calipers is the feel, pedal response and ability to modulate the braking.

Cool--I'm looking forward to finding out for myself! Parts have started arriving. ETA on all the other parts is between now and Tuesday.

 

[Stu_Rock]

Well, everything I ordered came and I test fitted one side. After drilling/tapping the new caliper bracket, the entire assembly fits perfectly (F-body bolts are M12-1.75; C/G/H/K/W-body bolts are M14-2.0).

The catch is that the old brake hose is too short. I have on order the hoses from a 1990-1993 Cadillac limo/hearse. By the specs, they should fit. If they don't, I'll have to get some custom lines.

 

[Stu_Rock]

Well, it is done. The hearse hoses did the trick, though I had to reposition the brackets that were crimped onto the hoses. That was a chore. I also had to re-index the hose-end bracket on the right side of the car. The left side was fine as-is.

How does it work? I would say the pedal feel is a little different. It's more linear; I get some initial bite and it increases nicely with more pedal distance. I think I can brake a little harder before lock-up as well.

How much of the change is because of the swap? I don't know. It might just be a consequence of being new parts. The new pads are the OE-grade ceramics from Raybestos, and I replaced the rotors as well (Wagner, now Chinese-made).

I am still uncertain if I can detect any ride difference. The new aluminum 2-pot calipers are 10.2 lb, while the old cast iron grabbers were 14.4 lb. The wheels are surprisingly light on this car and the control arms are aluminum, so the caliper switch amounts to a meaningful change in unsprung mass.