Modifying disk brake pad carriers?

[Root Moose]

I think I've got a rear disk setup I can deal with but there is one problem that I'd like to address. I'm hoping some people here have come across this type of thing in the past when preparing vehicles.

This is the pad carrier for a 1994 Buick Regal Custom mounted on a SWB TracKick front rotor (as applied to rear axle):

http://moose.ca/albums/albums/Projects/XJ_Build/Rear_Disks/Buick_calipers/pad_carrier.jpg

( apologies for the crappy image quality - kid's camera is less of a loss if it gets wrecked in the garage )

You can see that the pad outer edge does not line up with the outer edge of the rotor. In order to maximize the swept area I should move the pad inward.

Here's a couple shots of the pad carrier from different angles to show the distance I'd like to move the caliper inward (~3-4 mm):

http://moose.ca/albums/albums/Projects/XJ_Build/Rear_Disks/Buick_calipers/carrier_pad_gap.jpg

http://moose.ca/albums/albums/Projects/XJ_Build/Rear_Disks/Buick_calipers/carrier_down_oblique.jpg

What I'm thinking about doing is machining the chamfered surface of the bottom of the pad carrier where it sits near the rotor hat. It's the semi-circular area at the bottom of the pad carrier in this image:

http://moose.ca/albums/albums/Projects/XJ_Build/Rear_Disks/Buick_calipers/carrier_up_oblique.jpg

All that setup, now the questions...

Is it advisable to machine the pad carrier? Some pad carriers are not closed along the outside bottom of the carrier so maybe it isn't a big deal to remove material? My understanding is that this style of carrier is better at preventing rotor/carrier warp, particularly with non-vented rotors.

If it is practical modification should there be any post machining operations performed? I'm thinking re-radius the machined edges similarly to the existing radii on the pad carrier as well as bead blast the machined surfaces for stress relief and surface re-hardening. Overkill?

Should I add more material (welded) to the carrier to replace the material that is removed? I was thinking along these lines provided there is enough space:

http://moose.ca/albums/albums/Projects/XJ_Build/Rear_Disks/Buick_calipers/modified_carrier.jpg

Post weld operations?

I did see some mention of pad carriers being modified on the web but you know what they say about things you read on the web...

Just for shits and giggles and because I'm jazzed about actually making progress on the project, here's a quick snap of the front brakes:

http://moose.ca/albums/albums/Proje...ks/Buick_calipers/wj_calipers_on_knuckles.jpg

Getting there...

 

[tealcherokee]

bigger rear rotors

 

[Root Moose]

bigger rear rotors

That would be the obvious thing but...

do you know of a non-vented, 5 on 5.5" rotor I could try?

 

[tealcherokee]

That would be the obvious thing but...

do you know of a non-vented, 5 on 5.5" rotor I could try?

not off the top of my head, but go to the parts store, they can look them up by sizes

 

[Dirk Pitt]

ZJ rear disks are non-vented, but 5 on 4.5...

Could they be redrilled to 5 on 5.5? It's been a while since I had mine off.

 

[cracker]

I re-drilled an explorer rotor.

 

[CrazyXJ]

currie redrills for 20 bucks and they will be perfect

 

[egon]

WJ rear rotors, 12" diameter, 5 on 5", 6 3/4" diameter hub surface, 2 7/8" over all height

Might that work if redrilled?

--Matt

 

[Root Moose]

I ended up switching to vented Suzkuki Sidekick calipers and rotors, Wilwood spot/ebrake calipers. These rotors fit over the hub assembly without any machine work.