1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder

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My brakes have been acting funny for the last two days. Yesterday I pulled out of the drive way and the peddle went to the floor with no resistance. One quick pump and they were right back where they should be.

I have always been happy with the brakes in the Jeep. The pedal was close to the top and nice and hard (this Jeep has manual brakes with disk in the front).

In driving occasionally I would get a pedal that went half way down and was a little soft.

Fluid in the master was right up there and clean. Looked on the inside of the firewall and found fluid running down the metal.

So the research started. Turns out in 1983 there was two different master cylinders installed in Jeeps with manual brakes. Delco with a 1″ bore, and Bendix with a 11/16 bore and they were stamped with 2111. I found that out because the parts guy looked up the wrong year Jeep.

Seems 1984 should only have come with the Bendix with the 11/16 bore, and have the stamp 2111.

Carefully looked over the master cylinder in the Jeep and I find no stamp.

1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8712 So here is the original master cylinder in the Jeep
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8724 This is the leak I found on the inside.
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8727 I removed the fresh air diverter from under the dash between the steering column and the ash tray and found a better view and better access to the rod and nuts holding the master cylinder to the fire wall.
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8726 The new master cylinder. Even though research says it should be stamped with the numbers 2111 I did not find that stamp on either the new or old master cylinder
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8729 First task is to get to and remove the cotter pin holding the push rod from the master cylinder to the brake pedal
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8731 No an easy task for a small guy like me, decided to remove the driver’s seat to provide better access. I was well worth the effort.
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8735 Time to remove the old fluid from the old master, spread towels under the master and over the fender. There are many ways to do this, but what I do is use paper towels to soak up the fluid.
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8739 This is my setup to bleed the new master cylinder. It took about fifty strokes to finial not get any air bubbles
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8742 New master cylinder installed, hardest part of the whole operation was getting the cotter pin back in. The master cylinder is through bolted through the fire wall. The nuts are not captured so they must be held while tightening the bolts. I was able to insert the outboard bolt through the master cylinder, fire wall and reach through the door opening and put the nut on inside the Jeep.

I did have to have a second person hold the nut while doing the finish tightening of those bolts.
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8744 The brake lines were bled until I got clean new brake fluid coming out of all four bleeder screws, here you see the small guy checking for leaks
 1984 Jeep CJ-7 Progress 2015 09 05 Master Cylinder DSC_8747 Installation is complete. I have driven the Jeep and do a panic stop. All wheels lock up.

I not really happy with the feel of the brake pedal. It is not as hard as I would like (no power brakes) Pedal should be rock hard and braking should result from the pressure exerted on the pedal with no travel. I still get some travel in the pedal. I went through a full quart of brake fluid. I will buy some more and re-bled the brakes again.