: Decent/ big (?) brakes for my 94 FWB



425 Dual Quad
09-14-11, 09:08 PM
Hi all!

I've never been happy with the stopping power of my 94 Fleetwood - it's always taken a bit too long to come to a halt for my liking and as for slowing down rapidly for the twisties forget it!

Recently it's developed a lot of front end judder when the brakes are midly warm. It started seriously after about 6 hours of mountain driving. I guess the rotors are overheated and warped? I've also had a persistent ABS/ Traction orange warning light coming on in the wet that concerns me. Cleaning out the left rear drum stops it for a bit for a month or so.

I've also had the left caliper rattling on the mount so I replaced the mounting pins, bushes and rubber mounting bushes on it , and the right caliper, with a hardware kit. The old rubber bushes were worn noticably thinner.

Maybe the hoses just (or also) need replacing. I've got to thinking of replacing the rotors, hoses and calipers.

I recently got a pair of repalcement Wilwood calipers for a 1980 Firebird which were noticeably bigger than the standard calipers and didn't break the bank. They also fitted the standard mounts and rotors altho needed to use 7/16" hoses instead of the metric ones. I've noted they are also available for the 99-6 Fleetwood with HD brakes (the D52 calipers) but on closer inspection they use the same size pads as the stock Delco pads for the 68-96 Cadillac - 5.35" x 2.08" ! Maybe the twin pistons provide more clamping force but I'm not convinced for $350 the pair!

Regarding rotors, there does appear to be 2 rotor widths - 1.04" and 1.25" - what is that? Is one the HD brake option with the 1.25" rotor? Will the thicker rotors go on OK and if so what Calipers do I need? I have FE2 suspension currently (the standard set up).

I want the biggest I can get inside the standard wheels - I have the 15" vaned optional alloy wheels if it makes a difference.

Is there a difference in wheel bearing sizes depending on what size rotors I get since the replacement rotors appear to be all in one with the inner and outer wheel bearings?

What about hoses? Are the new nylon hoses as stong as the steel braided ones? For some reason the DOT doesn't like steel braided hoses here - offroad use only!

What have those who have modified the handling on their 94-6 FWBs done and investigated?
Thanks all, Nick

jayoldschool
09-14-11, 09:39 PM
The brakes on these cars are undersized. They should have stuck with the thicker rotor from the 70s.

The thicker rotor is the old rotor from the 71-76 full size. It came on the limo package for your year. You need to change the spindle to use it. No ABS. Changing the caliper will not give you better stopping. That only comes from increasing the swept area. That is done by increasing the diameter of the rotor. Thicker rotors will not improve the first stop. They will, however, shed more heat allowing the stop length to remain the same for longer.

There are quite a few big brake options for the Impala SS/Caprice/etc that will work on your car. You will have to go with a larger diameter wheel, however.

There are approved braided hoses, check Summit for the part number.

New rotors, and good pads, will go a long way to improving your brake situation.

425 Dual Quad
09-15-11, 05:10 AM
Jay,
Thanks - much appreciated.

I was thinking these brakes are undersized. However I don't want to go to the lengths of changing the spindles, wheels or losing the ABS - ABS is a mandatory requirement, if fitted, here. Thanks for the advice on caliper - I was thinking the same.

So I'm pretty much stuck with what I've got, apart from new hoses. So I guess a set of Delco replacement rotors is the requirements (or what do you think about the slotted drilled Raybestos rotors on RockAuto for $70 each vs the standard ones for half that?) and new hoses. (I just ordered a bunch of stuff from Summit last night for the other cars!!)

What pads do you recommend? (I've just put in a new set of Delco Durastops). I'd like to keep the dust low since it's trashing the wheels.

regards & thanks, Nick

jayoldschool
09-15-11, 10:37 AM
I don't like drilled/slotted on our cars for the simple fact that they remove material and mass from the rotor. That means less friction surface, and less material ti dissipate heat.

I like semi metallic pads, but they will dust. Check into EBC, they might have a nice performance pad that won't dust much.

Fresh brake fluid and a good bleed will help feel, too! Don't forget to turn the rear drums, install new shoes and adjust.

425 Dual Quad
09-15-11, 11:02 PM
Jay,
I agree with you on the slotted/ drilled rotors issue - the holes cause cracks also.
Tell me, before I order a set of stock replacement rotors - why do I lose the ABS with the larger, older size HD rotors? And are they thicker so they won't fit inside my stock calipers?

Thanks, Nick

turbojimmy
09-16-11, 07:23 AM
Jay,
I agree with you on the slotted/ drilled rotors issue - the holes cause cracks also.
Tell me, before I order a set of stock replacement rotors - why do I lose the ABS with the larger, older size HD rotors? And are they thicker so they won't fit inside my stock calipers?

Thanks, Nick

I think that when you replace the spindle and mounting bracket you lose the provision for the wheel speed sensor. It can probably be done, but there has to be a reason GM deleted the ABS and Trac Control on all the V4U (commercial chassis) cars. I do have to say that both limos I've had stop great for such big cars. I can also say that they will warp Chinese-made rotors instantly. Go with Delco stuff if you can.

jayoldschool
09-16-11, 12:00 PM
TJ's correct on the ABS sensor.

The thicker rotor will not fit in the narrower 77-96 caliper.

csbuckn
09-16-11, 12:18 PM
So, if you don't want ABS, could you swap over the spindle, rotor and caliper and bolt it on the stock ball joints and tie rod?

turbojimmy
09-16-11, 02:33 PM
So, if you don't want ABS, could you swap over the spindle, rotor and caliper and bolt it on the stock ball joints and tie rod?

The ball joints and tie rods are different, too.

jayoldschool
09-16-11, 05:38 PM
Yep, I looked at the setup on my 71 Pontiac to see if I could use the thicker rotor on the later cars. Not happening. HOWEVER... there is a couple of custom options. One of the wagon guys has come up with a way to use the thicker Astro van rotor, and one of the Impala SS guys has made a 1.25" rotor that will work. I'll dig up the links later...

Cadillacboy
09-17-11, 04:41 PM
.I had some issues w/ our old tires as well . After replacement tires itself the car stops smoother and neater in a proper way . However, I do feel judders too . Also, compared to European cars , brake pedal in these rides feel mushy , I mean it's kinda soft but Mercedes, Jaguar have firmer brake pedals set up

425 Dual Quad
09-21-11, 04:37 PM
So, all in all I think I'm stuck with using the standard rotors. Will have to get a pair of replacement Delco ones I suppose.
Thanks All

425 Dual Quad
09-21-11, 04:42 PM
So, all in all I think I'm stuck with using the standard rotors.&nbsp; Will have to get a pair of replacement Delco ones I suppose. JM4 is the standard suspension code isn't it? (J55 the HD one?) <BR>Thanks All

425 Dual Quad
11-10-11, 06:58 PM
Well I got my new front discs on together with new pads, new hoses and new inner and outer bearings. All Delco Durastop stuff throughout. And new tyres whgich I got a couple of weeks ago. The new tyres didn't make much difference. However the new discs and pads do! The car stops smooth and even no more pulsing and feeding back of the pedal at all. The old discs had very heavy scores in them and there were huge quarter inch deep grooves worn in the new pads.
So all good, except ...... and I'll post separately on this - the rear end is hard as a rock! Very skittish and bouncy. It is like the level ride air shocks are fully pumped up and won't go down. The car was up on a 2 post lift with all 4 wheels hanging down whilst the brake work was being done. So the shocks were fully extended. The level ride sensor looks all in its normal position. We took the 30A fuse out from the fuseboard under the hood but no compressor kicking into action and no valve operating to let out hte air. We took an air line off the left side to try and let the air out but nothing. Shocks are hard as a rock. Can the shocks 'set' in the fully extended position like this? Any ideas gentlemen?

regards, Nick