73-87 Rear Disc Brake Conversion Problem

[Ricko1966]

I haven't seen the procedure laid out like that before either. I'd assume that they want you to do it that way, just because it seems more professional than manually ratcheting the lever a whole bunch of times. But that's just my assumption.

I've worked on calipers where you actually were setting how far the piston retracted via adjustment with a set screw,it was done so that the brakes didn't retract the piston two far,the set screw was a physical stop so the pads could never retract more than. .004 from the rotor,this adjustment was made while levering the caliper towards the inside so the inner pad was pressed firmly against the rotor. That was why I mentioned adjustment, Im assuming the Cadillac calipers have a similiar adjustment,other than just ratcheting the ebrake lever.

 

[bucket]

I've worked on calipers where you actually were setting how far the piston retracted via adjustment with a set screw,it was done so that the brakes didn't retract the piston two far,the set screw was a physical stop so the pads could never retract more than. .004 from the rotor,this adjustment was made while levering the caliper towards the inside so the inner pad was pressed firmly against the rotor. That was why I mentioned adjustment, Im assuming the Cadillac calipers have a similiar adjustment,other than just ratcheting the ebrake lever.

It's been many years since I messed with any. But I don't recall being instructed by the wise old timers that I worked with to remove the lever and do that procedure. The '82-'88 F-body had a very similar caliper, just a little smaller. They don't work very well there either.

 

[AuroraGirl]

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These are both supposedly used at around the same time, so does your calipers OP by chance look like either

 

[Ricko1966]

It's been many years since I messed with any. But I don't recall being instructed by the wise old timers that I worked with to remove the lever and do that procedure. The '82-'88 F-body had a very similar caliper, just a little smaller. They don't work very well there either.

Like

It's been many years since I messed with any. But I don't recall being instructed by the wise old timers that I worked with to remove the lever and do that procedure. The '82-'88 F-body had a very similar caliper, just a little smaller. They don't work very well there either.

This was a common problem with 914 rear calipers,people didn't realize you had to physically set the depth of the piston with a set screw,or the rear brakes worked like crap. So on initial setup you'd set the calipers to. 004 clearance,I'm wondering if the cadillac calipers are adjusted similarly,thats why they say to pull the arms and mess with that bolt.. The ebrake lever is below that adjuster in red. The original setting was .008 revised to .004 but no matter if you didn't set it the rear brakes were crap.

 

[Bennyt]

Sounds like a dumb question, but I have seen this happen.

The way you have them installed, are the bleeders on the top or the bottom of the caliper? Some rigs can actually allow the caliper to bolt on upside down.

Yes, they can be mounted upside down and I have done that purposely on my own truck. It allows you to run the p-brake cable over the axle so it doesn't snag off road. To bleed, I'd unbolt, turn bleeder side up, place a 2x4 or block in between the pads, and then reinstall.

Additionally, the parking brake doesn't work very well unless you install a ratcheting type lever or e-stopp as the existing pedal doesn't have enough travel.

 

[HOTFOOT]

Sounds like a dumb question, but I have seen this happen.

The way you have them installed, are the bleeders on the top or the bottom of the caliper? Some rigs can actually allow the caliper to bolt on upside down.

I want to know more about the pad being backward.

 

[GreenRacer 64]

might not be the right volumes being used
Maybe a brake line diameter or bad piston seal(s) situation
The front calipers are still the original non-low drag brakes right? Hows your pushrod lengths

Thanks for the questions. The front calipers are original as it the pushrod length. When I installed the new master cylinder, I put the bullet spacer in so it is set up exactly as it was from the factory.

 

[GreenRacer 64]

I want to know more about the pad being backward.

Yes, they can be installed backwards but they are installed correctly with the bleeders are at the top.

 

[GreenRacer 64]

I haven't seen the procedure laid out like that before either. I'd assume that they want you to do it that way, just because it seems more professional than manually ratcheting the lever a whole bunch of times. But that's just my assumption.

I've followed the e-brake proceedure that was posted here. I literally have 1/32 of play in the ebrake lever. The pads are so tight to the rotor, I can barely turn the disks. I also bled the brake after the ebrake proceedure was complete yet the problem still exists.

 

[GreenRacer 64]

The Eldorado calipers have a bad habit of not staying adjusted. So when you hit the pedal, it's soft until the pad reaches the rotor. Do you have the parking brake hooked up and functioning?

The ebrake adjustment has the pads so tight to the rotor that I can barely turn the rotor. I've read that if they aren't tight, the pedal will be soft so I've made them as tight has possible..

 

[cadillac_al]

That has to be too tight. I would at least adjust it so the wheel turns easily and let the park brake work as crappy as it wants to. If the pads drag that will heat up the pads and rotor and drag even more and just cause headaches.

 

[Turbo4whl]

Pennsylvania state safety inspection requirement, parking brake must hold on a 20% grade. That is an 11.3 degree angle.

... but the park brake has always been very weak. I always assumed that was just the nature of the Cadillac rear disc brake system.

Additionally, the parking brake doesn't work very well unless you install a ratcheting type lever or e-stopp as the existing pedal doesn't have enough travel.

That has to be too tight. I would at least adjust it so the wheel turns easily and let the park brake work as crappy as it wants to.

^^^ This is a fail. ^^^

As far as bleeding, I worked on a rig once and I bled and bled and just could not get a firm peddle. I decided to give up and drive the vehicle to a shop and pay them to try. 2 seconds into driving it I realized I was chasing a ghost. The brake worked GREAT, and although the peddle could be pressed down farther than I was expecting before it became firm, the brakes would all lock up long before that. So brakes lock at 3 inches, but if I pushed hard I could get the peddle to go down 6 inches. I recommend driving it and see how it responds. After all, the whole idea is to get good brake performance, so if they perform really well - then there is no more work to be done. Fixed is fixed.

This is how the light duty Fords are when bleeding.^^