Front Chevy Brake Caliper Issues

[Toyaddict71]

Hello all, I have the chevy disc brake conversion. on a '74. I replaced the calipers and pads, replaced the fluid and bled the lines. But now have almost no braking. Barely enough to hold still at idle. Even at 2mph it'll barely bring it to a stop. The outside pad opposite the piston on both fronts isn't tight. Has a slight gap and i can move around slightly with a screwdriver even with brake pedal pressure. I hoped it would tighten up with bleeding, but nothing. Maybe wrong pads? They look like the old and seemed to install clean enough. I did not replace rotors as they seem to be descent. Any experience/advice is greatly appreciated. Thanks!

 

[serial car restorer]

Calipers are supposed to slide on the 2 pin sleeves—obviously they are not. There should be 2 sleeves that go in the mounting ears that can move, sliding on o-rings in the ears. The 2 pins tighten down on the sleeves. Either your hardware is wrong, or you have assembled them wrong.

 

[JeepGuy]

Hello all, I have the chevy disc brake conversion. on a '74. I replaced the calipers and pads, replaced the fluid and bled the lines. But now have almost no braking. Barely enough to hold still at idle. Even at 2mph it'll barely bring it to a stop. The outside pad opposite the piston on both fronts isn't tight. Has a slight gap and i can move around slightly with a screwdriver even with brake pedal pressure. I hoped it would tighten up with bleeding, but nothing. Maybe wrong pads? They look like the old and seemed to install clean enough. I did not replace rotors as they seem to be descent. Any experience/advice is greatly appreciated. Thanks!

Did you grind down the Knuckle so the Caliper can move back?

 

[Toyaddict71]

Calipers are supposed to slide on the 2 pin sleeves—obviously they are not. There should be 2 sleeves that go in the mounting ears that can move, sliding on o-rings in the ears. The 2 pins tighten down on the sleeves. Either your hardware is wrong, or you have assembled them wrong.

OK. Going to break them back down and take a look. Shound they be greased?

 

[Toyaddict71]

Did you grind down the Knuckle so the Caliper can move back?

I've had this truck 20 years and the conversion was completed well before then. BUT the caliper is up against the knuckle. You're saying iit have been ground down for more movement? How much?

 

[Toyaddict71]

So I just looked at old calipers. they are well aged so is hard to tell but the calipers were ground down. odviously new ones are not. THANKS for the heads up!

 

[serial car restorer]

Normally, it's better to grind the knuckles rather than the calipers. Take a look at the instructions for one of the kits that use the GM calipers from WH or Tom's.

 

[Toyaddict71]

Normally, it's better to grind the knuckles rather than the calipers. Take a look at the instructions for one of the kits that use the GM calipers from WH or Tom's.

Well I already ground the calipers. It doesn't require much . Had them reinstalled in less than 5 minutes of grinding per caliper. I can see why knuckes would be better though. If it was originally done that way, never would have had an issue with new calipers at all. i never would have spotted that on my own. Thanks so much for the help. Working great now.

 

[JeepGuy]

I've had this truck 20 years and the conversion was completed well before then. BUT the caliper is up against the knuckle. You're saying iit have been ground down for more movement? How much?

I've been having brake issues as well on my 74 with the chevy conversion and that was one of the first things I went back and double checked.

Sounds like you got it all worked out either way. Below is what the knuckle usually ends up looking like to clear the chevy style calipers.

Out of curiosity, if you did have an old caliper to compare it to, did they look the same or was the body of the caliper different. I wonder if there is a significant difference in year range between the calipers, or if whoever did the original conversion just ground the calipers down as well.

 

[Toyaddict71]

I've been having brake issues as well on my 74 with the chevy conversion and that was one of the first things I went back and double checked.

Sounds like you got it all worked out either way. Below is what the knuckle usually ends up looking like to clear the chevy style calipers.

Out of curiosity, if you did have an old caliper to compare it to, did they look the same or was the body of the caliper different. I wonder if there is a significant difference in year range between the calipers, or if whoever did the original conversion just ground the calipers down as well.

View attachment 941635

sorry for delayed response. The calipers look the same. The amount of material I had to remove from the calipers is pretty minimal. Interesting enough, I went through 2 sets of calipers. The first set just would not quite fit. I thought they were the wrong ones, like a 1/8" off, but even the second set was really tight to get on. They were hitting the knuckle, after I ground it down, fit lika a glove. I'm sure the first set was just slightly thicker right where they made contact but would have fit fine other wise. In your pic, the extended part out from the caliper is ;pretty much all I took off.