Need help, Have almost no pedal with Cadillac rear disc..

BlackFox5.0

BlackFox5.0

Founding Member
Aug 7, 2000
3,514
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Massachusetts
#1
I have 73mm Calipers in front right now, with and SVO (1 1/8" bore) Master Clyinder. I just put Cadillac rear calipers on the car and they are working like 2%.

I pulled up on the e-brake many many times, bled the brakes like crazy, played with everything we could think of, and still no pedal, so tested the brakes by moving a little, then I took it for a slow drive, the pedal goes right to the floor, then there is like 1" of pedal that brakes start to work, if I slam on it, the front brakes will lock up, nothings seems to be working in the rear.

I am a bit afraid to be driving the car like this. If I pull the ebrake up the car doesn't seem to slow at all (rolling in neutral). I am thinking my MC is too big, but then again i have similar brakes to the SVO :shrug: I REALLY don't want to change the MC :(
 

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#2
you may have blown your master, when you bleed your brakes you shouldn't push the pedal all the way to the floor, you should only go 1/2 the way to 3/4.. You can rupture your seals in your master if you jam it to the floor while bleeding.. I've seen it a hundred times.... Are you getting any fluid out of the rear while bleeding? I've never done a conversion like that, but i'm just trying to help..
 
#3
I was getting fluid out of the rears, no air anymore though. On Matts site he said "The stock mounting position on the 8.8 will trap air in the calipers. Be sure to use a C clamp or pad spreader on the piston to keep it from moving while bleeding"

We mounted them on my car and bled them. I told my father we had to take them off and bleed them like Matt says, but he said no. I still think there might be air in them, but it's not coming out how it is.... :( I really need to fix this.

The MC is not blown, it works fine, and it's a brand new reman.
 
#4
cool about the m/c , I've never had to hold a piston to bleed it, your bleeding it with all the brakes together right? the pads hitting the rotors should hold it enough.,

anyways, try this please. fill it with fluid, crack open the right rear,(don't pump the brakes or anything) and let it sit for a 1/2 hour and check it, you should be getting a steady drip, then shut that one,
top off fluid, and do the same for the left rear. I would then close it up and bleed your fronts also..right front, then left front.. let me know after... [email protected] , tony
 
#6
The thing that Matt is decribing is how the bleeder is not at the top most position, and air can get trapped inside, which is all I can really think it is. Everything else is fine, with no leaks. I'll have to try bleeding them off the car, what a pain this is becoming.

On the track deal, I don't go to NED a lot, I only went 2 times with my car 2 years ago now....I am interested in what I can do now, hopefully I can break the 13s, I'm hoping mid-13s but im not really the dragstrip type, too far of a drive, esp if something breaks, andit's not as fun as cutting corners :D

Here is a pic of the rims I put on :)

attachment.php
 
#7
nice wheels, like I said , i don't have experience with that setup, but every car I've worked on, from toyota to dodge to porshe, usually will alow the air to come out on its own by gravity bleeding it..
What are the wheels on the front? white 5 stars? Are you selling those? JK Those would look good on my triple white!! LoL.. talk to you later,, tony
 
#8
Actually I am selling my White ponies, I had them painted at a body shop, they came out good except for one, which isn't that bad really, I should have wet sanded them and polished them up, the paint is still new though :)

I'm asking $400 with the front tires, the rear tires are no good, I will be getting rid of those tires so I can ship them if I have to.
 
#9
tvmango said:
nice wheels, like I said , i don't have experience with that setup, but every car I've worked on, from toyota to dodge to porshe, usually will alow the air to come out on its own by gravity bleeding it..
Click to expand...

Yeah but you are forgetting something here. These are GM calipers being used on a FORD. They are not sitting at the correct attitude that they were designed for on the Caddy. The bleed screw isn't in the right place to allow for natural bleeding.

Gotta take em off, point the screw up and bleed
 
#11
Did you gutt the stock prop. valve before adding the adjustable prop. valve? I would go to the hardware store and buy a couple of plugs/bolts that fit the ports of the M/C. Start by plugging both ports and see if you get a firm brake pedal. It should be solid as a rock with both ports plugged. Next remove the plug for the front brakes and connect the front brake line. Again, the pedal should be very firm. Lastly, remove the rear plug and connect the rear brake line. If the pedal drops to the floor you know the problem lies after the M/C. See if you can get yourself a brake pressure gauge tool. It connects to the nipple on the brake caliper and will give you brake pressure readings to determine if you have enough pressure to engage the calipers.
 
#12
Mustang5L5 said:
Yeah but you are forgetting something here. These are GM calipers being used on a FORD. They are not sitting at the correct attitude that they were designed for on the Caddy. The bleed screw isn't in the right place to allow for natural bleeding.

Gotta take em off, point the screw up and bleed[/QUOTE

I didn't forget anything here, maybe you should read all of the posts and not just skim through.... I have said a few times,,I've never delt with these clalipers in this situation, I was trying to give him a hand. Nobody else was..

What ever,, good luck with project.. You have a professional here to help you now...altitude!!! Ha :rlaugh:
Click to expand...
 
#14
Because:

I couldn't find Mark VII axles cheap.
I was orginally going to use this for 4-lug, which was what I thought was the best option at the time.
I could use this setup for 5-lug as well, which I ended up doing.
The caddy calipers are bigger than the Mark VII, so this is the best way IMO to go while the next step up would be like Baer or Willwood.
I autocross, and brakes play a big part, esp with all the horsepower and weight my car has.


I will try to get the brakes beld today, hopefully they will go ok....
 
#17
anyways, I got my brakes working, but I have to yank on the e-brake with 2 hands to make it hold the car on my driveway, which is on a hill......I still leave it in gear though.

There was a pocket of air in the caliper, we had to take the caliper off and let it gravity bleed, then bled it like normal a little bit, and I have a good pedal now :)
 
#19
A bit better, I haven't really tested them, I'll let the pads break in first.

But i came down to my road, I was doing about 30mph, and got on the brakes about 10 feet beofre the road I had to turn down, it the car stopped at an incredible speed!

I did the same right bfore my driveway, and the rears locked up I think I'll have to test them again, and adjust my prop valve accordingly
 
#20
yes, you have to remove the rear calipers to bleed them initially or if you get any air in the lines with most rear disc systems! I have heard of needing to do this on the factory F bodies frequently.

So tell your dad to listen to the advice posted from people that have done the conversion.

For the ebrake, read the section where I had to re-adjust the lever on the caliper. Made them work a lot better. What are you using for cables? Did you modify the handle at all?

Other than that, they work great. They are a bit of a PIA to setup and bleed, but work great once you get the kinks out of the setup!
 
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