Rear disc conversion

[letitsnow]

260-11179. I am set up to run my own brake lines and flare whatever I need to etc.. It might be tougher to install if you aren't.

If you want to keep your abs, i'd suggest that you try an NBS (disc/disc) master cylinder before the adjustable prop valve. If my oem master cylinder causes any problems, it'll be replaced with an NBS one, then i'll have to re-adjust my prop valve.

 

[Clevor]

260-11179. I am set up to run my own brake lines and flare whatever I need to etc.. It might be tougher to install if you aren't.

If you want to keep your abs, i'd suggest that you try an NBS (disc/disc) master cylinder before the adjustable prop valve. If my oem master cylinder causes any problems, it'll be replaced with an NBS one, then i'll have to re-adjust my prop valve.

Ok, took my wheels off and looked at caliper. On application, caliper tries to rotate in perpendicular to axle. Caliper piston also gets cocked in bore. Definitely not square with plane of rotor. Contacted Shawn at lugnut4x4 and he suggested I wack the bracket ears with a hammer to square it up or use a pipe wrench to bend them. I'm not doing that. Not very precise and in my opinion, the brackets should have been correct to start with. So I have ordered machined shims to put between the bracket and axle tube on the two rear bolts. This will force the caliper bracket threaded holes to become perpendicular to the brake rotor when I tighten the bracket bolts. If that squares away my two issues then I will remove the brackets and have them machined on the mounting face at an angle. I'm a mechanical engineer by trade with 17yrs in machine shop/punch press repair business so I know this can be done. According to lugnut4x4, once the brake pads are parallel with the rotor surfaces my pedal travel will be more useful in stopping and not in aligning and then stopping. Email me if I would like vid showing misalignment. Compressed it but form won't allow extension. I will keep u posted.

 

[Frank Enstein]

A few things come to mind.
1) make sure the calipers are floating properly. Check the front calipers as well.

With the caliper bolted down but with NO PADS make sure you can slide the caliper on the pins with one finger.
If not, shine up and lubricate the pins/sleeves.

If they don't move properly, the brake pedal can be low and soft and the calipers may drag.
On my Firebird I simply removed the o rings from the mounting areas.

2) If the caliper has a built in parking brake use it! The caliper adjusts when the barking brake is applied. If you don't the pedal will be low and soft

3) Braided brake flex hoses and the Earl's Solo Bleed bleed screws can make a substantial difference in pedal feel.
Put them on one vehicle and you will put them on everything else you own. You've been warned.

4) Check the brake line routing. In a perfect world the brake hoses would run downhill all the way to the calipers.
In reality brake lines generally run downhill then up again to the caliper. If you have a high spot in between it can be very difficult to bleed the bubbles out.

Good luck!

 

[Clevor]

A few things come to mind.
1) make sure the calipers are floating properly. Check the front calipers as well.

With the caliper bolted down but with NO PADS make sure you can slide the caliper on the pins with one finger.
If not, shine up and lubricate the pins/sleeves.

If they don't move properly, the brake pedal can be low and soft and the calipers may drag.
On my Firebird I simply removed the o rings from the mounting areas.

2) If the caliper has a built in parking brake use it! The caliper adjusts when the barking brake is applied. If you don't the pedal will be low and soft

3) Braided brake flex hoses and the Earl's Solo Bleed bleed screws can make a substantial difference in pedal feel.
Put them on one vehicle and you will put them on everything else you own. You've been warned.

4) Check the brake line routing. In a perfect world the brake hoses would run downhill all the way to the calipers.
In reality brake lines generally run downhill then up again to the caliper. If you have a high spot in between it can be very difficult to bleed the bubbles out.

Good luck!

Tkx for advice

 

[letitsnow]

Contacted Shawn at lugnut4x4 and he suggested I wack the bracket ears with a hammer to square it up or use a pipe wrench to bend them. I'm not doing that. Not very precise and in my opinion, the brackets should have been correct to start with.

I totally agree with you. It is frustrating.

 

[Clevor]

A few things come to mind.
1) make sure the calipers are floating properly. Check the front calipers as well.

With the caliper bolted down but with NO PADS make sure you can slide the caliper on the pins with one finger.
If not, shine up and lubricate the pins/sleeves.

If they don't move properly, the brake pedal can be low and soft and the calipers may drag.
On my Firebird I simply removed the o rings from the mounting areas.

2) If the caliper has a built in parking brake use it! The caliper adjusts when the barking brake is applied. If you don't the pedal will be low and soft

3) Braided brake flex hoses and the Earl's Solo Bleed bleed screws can make a substantial difference in pedal feel.
Put them on one vehicle and you will put them on everything else you own. You've been warned.

4) Check the brake line routing. In a perfect world the brake hoses would run downhill all the way to the calipers.
In reality brake lines generally run downhill then up again to the caliper. If you have a high spot in between it can be very difficult to bleed the bubbles out.

Good luck!

I see about the idea of using braid line. U want pedal travel to move caliper piston and not swell a brake line and move piston. Good idea.

 

[letitsnow]

Just don't confuse peal travel wit pedal feel. The rubber lines do swell, but only a little.

 

[Schurkey]

The rubber lines do swell, but only a little.

Folks remove old, damaged, failing rubber brake hoses, and replace them with new Teflon- (PTFE-) liner hoses with bright, shiny steel braid over the top. And they remark on how wonderful the new hoses are.

Well, yes, the Teflon-liner hoses ARE nice. But the biggest part of the difference was that the hoses removed were on the edge of failure. They'd have gotten a nice improvement in braking by simply replacing ancient rubber hoses with new rubber hoses.

Don't get me wrong...I've converted many of my vehicles to the Teflon-liner brake hoses. I've only installed a pair of rubber hoses (93 Lumina) in the last ten+ years--everything else has been Teflon.

My latest surprise was on my K1500, last fall. I had replaced the front hoses with Teflon-liner hoses during a major brake/suspension upgrade a couple of years ago; but I'd never bothered to do the rear hose. A broken bleeder screw in a rear wheel cylinder forced a wheel-cylinder change...which forced replacement of the brake tubing from the axle-end of the brake hose along the axle tubes. As long as I'm doing one tube to the right rear brake, I might as well do the tube to the left rear brake. As long as I've got the system open, and I have to bleed the thing, and both tubes are disconnected from the axle-end of the rear brake hose, I might as well disconnect the upper end, and replace the hose--since I've owned the replacement hose for two years already.

I put it all back together, and the brakes have never been better. The cynic in me says it was just the extensive brake-bleeding. More realistically, I think the old-but-OK-looking rear hose was starting to plug, restricting brake fluid to the wheel cylinders.

 

[Clevor]

I totally agree with you. It is frustrating.

Well, I did what I said I wasn't going to do and bent the bracket ears with a hammer. However, I've bent lots of metal with a hammer and this was going to take heat plus hammer. Rented oxy/act tanks and used cutting torch with carburizing flame to heat bend cherry red. Used adjustable parallel to make sure ear was parallel with rotor and wacked it with hammer. Not precise but it got the job done. Calipers hardly move at all on brake application. Very cold here and I don't have shop so may wait till warmer temps. Still, I shouldn't have hade to do that. I've been in stamping business for 17 yrs and the dies that make these brackets aren't right. Lugnut4x4 should have a jig to check every bracket made b4 shipment. Now that calipers are square, I can fine tune other system parts for better braking and shorter travel. Have a good day snow. I will update as time and finances allow.

 

[Clevor]

Well, I did what I said I wasn't going to do and bent the bracket ears with a hammer. However, I've bent lots of metal with a hammer and this was going to take heat plus hammer. Rented oxy/act tanks and used cutting torch with carburizing flame to heat bend cherry red. Used adjustable parallel to make sure ear was parallel with rotor and wacked it with hammer. Not precise but it got the job done. Calipers hardly move at all on brake application. Very cold here and I don't have shop so may wait till warmer temps. Still, I shouldn't have hade to do that. I've been in stamping business for 17 yrs and the dies that make these brackets aren't right. Lugnut4x4 should have a jig to check every bracket made b4 shipment. Now that calipers are square, I can fine tune other system parts for better braking and shorter travel. Have a good day snow. I will update as time and finances allow.

I meant to say in my reply that I will wait until warmer weather to recheck calipers and fine tune alignment if necessary. 30deg here.