69 J3600 brake help/opinion

[J20Hunter1]

I have a 1969 J3600 232,auto I have the truck running good ,now time for the brakes.It has power brakes on it, lines are pretty shot and I got 2 bleeder broke loose. I am just trying to get truck so I can drive it for a while .Trying to decide how far to go with mods.My question is there an easy swap for booster and master cyl.,I have a unit out of a 86 wagoneer.

[tgreese]

If you already have power brakes, switching to another master cylinder and booster will not help, I'd think. If you need a new booster, you can send the one you have to a specialist and fix it. Plenty of such specialists online if you search.

I would not assume that the parts from an '86 GW will have any family resemblance to what's on your truck, Jeep or not. These vehicles profoundly changed in 1974, and again in 1980. Maybe those parts will work if you are savvy and can adapt them. Seems very unlikely there is a well known and easy bolt-in replacement for what you have. Such things can be done, but expect to have to figure out what works and how to adapt it yourself.

Which brakes do you have, the 11"x2" or the 12"x2"? Parts are easy and cheap for the 11s and near impossible for the 12s. Brake lines are cheap if you make them yourself. Go Nicopp lines - a little more expensive than steel, but very easy to bend and flare. You can even reuse your fittings if they are in decent shape.

[J20Hunter1]

Thanks Tim. I think booster and master cyl is bad. I lucked out I have 11 inch brakes .Thanks for heads up on Nicopp lines,I can do them. will check on getting booster rebuilt . It has a 44 front and 53 rear so looking to mod down the road. I have a couple J20 donors. Thanks again for the help

[tgreese]

WIth 11" brakes and broken bleeders, suggest you throw away the cylinders and buy new. Inexpensive for those brakes; Dorman or Centric would be fine.

JMO - I'd fix the brakes so the truck is safe, and not worry about future plans. You may have trouble finding a new master cylinder for power brakes, if it's a factory setup. Another case where you may want to have your core rebuilt.

Went to the internet and found this place in less than a minute of searching. Not a rec, just an example.
https://whitepost.com/brake-sleeving-re ... -services/
There are places like this that serve classic car collectors and owners of oddball old cars (like Jeep trucks!)

[J20Hunter1]

I ordered a bunch of stuff from rock auto .I bought a FVP M1292 master cylI hpoe it is the correct one otherwise I will have mine rebuilt The truck is in good shape it was a one owner 39K on it .69 3600 Custom Cab 232 auto ,all original nothing hacked. Thanks for info

[Harry Dawg]

The booster and master cylinder from an XJ pretty much bolted right up on my 68'.

I had to buy some universal mounting brackets for a Plymouth, and also bore out the mounting hole in the booster push rod. Probably took me 2 hours.

Should be the same for your's.

I made a video on the swap if you are interested.
https://youtu.be/7jO3a07VuRw

[J20Hunter1]

Thanks for the help

[J20Hunter1]

Can I use the proportioning valve off of the XJ with the XJ master cyl and booster .Or do I need to just use the original block .This truck still has drum brakes on both axels

[tgreese]

Assuming the XJ was disk-drum. You can use a combination valve with drum-drum, but the disk-drum valve has a metering valve as well as a proportioning valve for the rear brakes. Look at page 9-20 of the '76 TSM here: https://oljeep.com/edge_76_tsm.html The CJs for '75 were all-drums and had a combination valve including a proportioning valve. The FSJs came with front disks and their combination valve also included a metering valve for the front brakes.

The plain block from your truck is just a distribution block. The combination valve was added by '74 to help prevent rear wheel lockup in severe braking. Up to you whether you want to go with the original config or upgrade to a proportioning valve. I would not use the XJ valve unless I knew how to remove the metering valve.

You can buy a proportioning valve for drum-drum systems. https://www.carolinaclassictrucks.com/d ... valve.html Search online and you will find additional sources. NB this has the connection for a brake warning light too.

A MC for disks may have a residual valve meant for disks in the front circuit. https://www.speedwaymotors.com/the-tool ... eeds/31069

[J20Hunter1]

Thanks Tim ,thats what I figured thought I would ask someone with more knowledge. Thanks again