Disk brake conversion completed

Hello all, I have been working for some time accumulating the parts for my brake conversion project and I have just completed it, including a new master cylinder from Kaisers. All went well with no snags at all. Here's the thing though, it has been decades since I have driven a vehicle without power brakes and I am not sure what good manual brakes should feel like. I think my jeep should be stopping better than it is now that it has disk brakes. I kind of expected it to be able to lock up the brakes and it doesn't. It will hold the jeep on a grade and stop, but I think it should be better. I am going to rebuild/replace the rear wheel cylinders next. After that I am out of ideas. Any comments or suggestions would be greatly appreciated. Thanks a lot. Tony L.

 

Knowing what components and from what you used to convert would be a good starting point to us helping you.
Did you use organic brake pads? If not that is part of the problem. Semi-metallic pads are for power boosted brake systems only.

 

I followed the "Early CJ Disk brake Swap" by Steve Lane which I found right here. He called for semi metallic pads which I have used. I am wondering now if maybe I did not bleed the system well enough, the pedal just does not feel right, or maybe I got a bad master cylinder. I plan on rebleeding for my next step. If I can get the pedal to feel right then I can re-evaluate. What do you think?

 

OK, I dug out the article which I followed. I don't recall how I found it as it was three years ago or so, but my search started here. Calipers from a 71-78 chevy 1/2 ton 4X4, caliper mounting brackets from a 73-91 1/2 ton chevy, rotors from a 77-78 cj (1 1/8 thick). As I said all the parts went together seamlessly. From all the various articles and postings which I have read this set-up seems to be a very commonly used one. I appreciate the pointer made about the organic pads and I will definitely get a set. I still plan to re-bleed just to certain that it is done properly. Thanks, as always I greatly appreciate any and all comments. Tony L.

 

I have used semi metallic pads on non power assisted brakes without any issues, and can lock up my tires, just stating my experience. The type of pads should have no effect on pedal feel when you are stopped. I'm not familiar with the article mentioned on the disc brake conversion, but does it state to use a residual pressure valve for the rears? Depending on the master cyl. you might need a proportioning valve as well. As far as rebuilding the rear wheel cyls., unless they are leaking why do it.

 

I have read about residual pressure valves and proportioning valves for this type of conversion. Some use them and some don't. I agree that the type of pads should have no effect on pedal feel when one is stopped. The rear wheel cylinders are not leaking but they are possibly forty five years old. I am just trying to cover all the bases and work this problem through one piece at a time. Thanks a lot for your thoughts.

 

The residual valve is only needed if the Master cyl. used was originally designed for 4 wheel disc brakes and you have drum brakes. The return springs on drum brakes will push the fluid back to the MC. Proportioning valve just fine tunes front to rear brake bias. It's cheap and easy to install, well worth it in my opinion to get good equal braking on a vehicle that wasn't originally engineered to have disc/drum or disc/disc brake system from the factory like early CJ's.

 

Same here! Organic pads and correct brake line routing made all the difference.

 

Pressing forward on figuring this disk brake problem out. I have re-bled the system, installed organic pads, and removed the 10 pound residual pressure valve from the master cylinder, and installed a 2 pound residual pressure valve in line to the front disks. On first test drive the brake pedal bound up on the master cylinder mounting bracket slightly, I addressed that. Anyway the brakes work very well now, when they work, but, my CJ seems to lose pressure at times for no apparent reason. I have only been testing the jeep on my long flat driveway. When this happens I re-pump the pedal several times, and then pressure comes back up. There are no leaks in my system. Any ideas, I am wondering if I need a residual pressure valve that falls between 2-10 pounds or maybe I need a more modern master cylinder. Any and all observations and suggestions will be greatly appreciated. Thanks a lot. Tony L.

 

When i did my disc brake conversion, i would lose pressure and have to pump the pedal to regain pressure. i found out on
a right turn, the caliper on the passenger side was hitting the axle bump-stop. i cut out a section of the bump-stop, problem
was solved.

 

2lb RP is all that's needed. Check out as mentioned above the caliper hitting anything with wheels turned. Also, does the pedal feel solid when pumped up or does it sink slowly? If it sinks then mc is suspect.

 

You nailed it, the bump stop is hitting the brake hose. I hope that once I fix this issue my pedal pressure problem will be solved as well. You wouldn't happen to have a picture of how you fixed yours? Tony L.

 

Hey guys, I did a little more searching in the archives here after Kaiser Krawler told me about the clearance problem with his bump stop. Kaiser Krawler nailed it, I think I have all the info needed now to complete the fix. I found pictures and lots of conversation. Thanks for the help.