Finally converting my 67 CJ5 to front disk brakes

Hello,

I assembled/built my 67 CJ5 in 1992 from a 67 and 73 CJ5, and various other parts. The frame is 67, but I am using the 73 tub. I also used the 73 11" drum brakes, Dana 30, and dual chamber master cylinder. The Jeep was assembled with 3.73 R&P. I recently decided to change to 4.56. While the Dana 30 was out, I stared at it thinking "Why would I put this back on the Jeep with disk brakes?". I called Olympic 4x4 Supply and they had recently received a 77-79 CJ for parts. I gave them the stripped Dana 30 and they set it up with 4.56 R&P and the disk brake hubs, spindles, etc. from the 77-79. They also gave me the OEM proportioning valve.

I have read the "Disk Brake Swap" article in the tech section of this site (see below). So I assume there is a 10-lb. residual-pressure valve in my 73 master cylinder that I must remove. I intend to use the 77-79 OEM proportioning valve. Are there any postings/pictures showing proper connection of this valve? I have an AMC Jeep Service Manual that covers the 77-79 CJ5 and CJ7 with disk brakes, but it does not show any pictures or diagrams of the location and connections to the proportioning valve.

Any help would be greatly appreciated.

Dale Chaudiere
Lynnwood, WA

Quote:

"Remember that if you are using a dual master cylinder from a drum-brake vehicle, you will need to remove the 10-lb. residual-pressure valve from the front port of the MC and plumb a 2-lb. unit inline to the front brakes I used a Wilwood PN: 260-1874. (The photo at left is from my incomplete installation). If you don't remove that 10-lb. pressure valve, the front brakes will drag, as there is no spring to return the calipers like there is in a drum installation. If you just remove the stock valve and don't install a 2-lb. valve like I did, you may end up having to double-pump the brakes all the time to get any pedal, as there is nothing to stop too much brake fluid from flowing back to the master cylinder when you release the pedal. Note the frame-mounted dual-chamber master cylinder from a 67-71 CJ-5. The purists may cringe; I just couldn't bring myself to put a single-circuit system back into my CJ-2A when I was going this far with a "restification". The old saying "no guts,no glory!" just doesn't apply here I'm afraid.'

 

When I did my disc conversion on my '73 D30 I used the Wilwood 2lb valve plumbed into the front brake line before it splits to left and right. I used the Wilwood proportioning valve plumbed into the rear brake line. The proportioning valve just lets you balance the braking action of the front brakes to the rear so the rears don't lock up too soon. The 2lb residual valve, as you stated, just maintains enough line pressure so you don't have to pump the brakes every time to get some pedal. This applies mainly to the frame mounted MC as it is lower in relation to the brake system and will allow the brake fluid in the lines to backflow into the MC. If you go to firewall mounted brake pedal you may not even need the 2lb, valve. The Wilwood proportioning valve is adjustable so you can dial it in, I don't know anything about the stock valve you acquired. One other thing. When you buy brake pads, get the organic pads. they will stop you much better than the metallics, unless you are using a power brake booster.

 

I appears that Olympic 4x4 Supply sold me an OEM combination valve metering valve from a 77 or 78 CJ5 or CJ7 (figure A) in the picture. I need to know which brake lines connect where on the valve.