What would you do?

[Hedgehog]

Honestly my lack of enthusiasm has slowed my CJ projects to a crawl. My disk brake front axle is mechanically installed. It's time to convert to Disk/drum hydraulics. I was going to go with a power assisted brake system, but the darned thing is way to big for my comfort. So, I've got a stock Disk/drum Master cylinder. I thought it would drop right in. Unfortunately the open ring that attaches to the brake pedal stud is to small. This leaves me with two possible solutions. Ream the ring, which is a tool I haven't got or cut the old one off and weld it on the new shaft. Naturally heat would need to be controlled in the process.

Reaming the hole would most likely be the best solution, but I'd have to pay a professional to do it.

Welding is my natural inclination. I have the tools and the process would be free.

 

[Torxhead]

Hedge, just how much material diameter wise do you need to remove?

 

[Lumpy Grits]

Why do you have to 'ream' and not drill?
How big a hole is this?
LG

 

[Torxhead]

I would go for reaming rather than drill for a better hole. Another possibility would be to install a brass bushing also. This is getting to sound expensive though.

 

[Hedgehog]

Not much, but a lot all at the same time. My calipers are hiding on me right now, surprising because calipers are a tool I use frequently. We are looking at about 1/6" and the loop hasn't got a much metal around it, maybe 1/8" to 3/16". It could be heated and stretched, but I can see a disaster there too.


Lumpy, as Torx wrote, it would be a cleaner neater hole. But I suppose it really doesn't need to be a nice clean hole, since there is a plastic insert that will go in the loop. I hear you now, no the loop in the new master cylinder is to small even without the plastic bushing. I imagine it's not really plastic, probably a Teflon impregnated material of some plasticky sort. My goal would be to open the loop up enough to reuse the old, (not so old, I put it in about 2.5 years ago) bushing.

 

[Lumpy Grits]

Just drill it out. Put some oil on it for lube and your GTG.
The drill will follow the hole. Real simple.
1/16" ain't much, and where the 'thin' parts are, carry no load when be'n used.
NO HEAT!
LG

 

[Hedgehog]

You have the proper size drill? That's the tricky part and drills in the 3/4" range aren't cheap.

 

[Torxhead]

Hedge, how about asking your local 4x4 shop or automotive machine shop for a price on doing it.

 

[Hedgehog]

That would fall under the ... "have a professional do it" category. You are right I should do that.

 

[Lumpy Grits]

What dia hole do you need to drill?
Can you post a picture or 2 to show exactly what you want to modify?
LG

 

[Lumpy Grits]

Hedge, how about asking your local 4x4 shop or automotive machine shop for a price on doing it.

Many shops won't touch that kind of work, because of liability concerns in deal'n with the brake system.
BTDT--
LG

 

[Woolyworm]

Just tell them it's for a washing machine!


Wooly

 

[Lumpy Grits]

Just tell them it's for a washing machine!


Wooly

LG

 

[jdcaples]

I'd get the professional quote and only worry about "declining the job due to liability" if it comes up. Around Seattle, machine shops are plentiful and I've no doubt someone would take the work w/o thinking twice.

-Jon

 

[tarry99]

Unfortunately the open ring that attaches to the brake pedal stud is to small. This leaves me with two possible solutions. Ream the ring, which is a tool I haven't got or cut the old one off and weld it on the new shaft. Naturally heat would need to be controlled in the process.

Reaming the hole would most likely be the best solution, but I'd have to pay a professional to do it.

Welding is my natural inclination. I have the tools and the process would be free.

There are many types and sizes of brake push rods in the after market.....the brake pedal arm can be removed by pulling the snap ring and removing the large shaft. The pin in the pedal arm can also be changed and replaced with a smaller diameter if you have the tools..........some brake push rods use a plastic friction sleeve while others don't.
Federal laws prohibit Any Welding on many Brake parts including push rods , for obvious reasons........
If your going non-power make sure you pay attention to maintaining the proper pedal ratio.......which should be about 5-6:1 depending on the sizing of the replacement components.
Should be an easy fix.

 

[Hedgehog]

The original master cylinder for the Drum/Drum set up was not an assisted system. It seems logical that replacing the unassisted Drum/Drum master with an unassisted Disk/Drum master would work ........ but then again

 

[tarry99]

The original master cylinder for the Drum/Drum set up was not an assisted system. It seems logical that replacing the unassisted Drum/Drum master with an unassisted Disk/Drum master would work ........ but then again

Using the correct sized Disk / Drum Master cylinder for your components , will still leave the pedal ratio questionable.

Disc brakes require a minimum operating pressure of 800-1000 PSI
Drum brakes require a minimum operating pressure of 400-500 PSI

In the simplest terms , The size of the bore in the Master Cylinder utilizes the brake force generated by your foot through the pedal ratio to generate the correct amount of operating force for your system.........assuming that AMC engineers did there homework , they would have taken the complete systems needs in both volume and pressure required to come up with the force needed at the pedal to make the system work correctly for the average person behind the wheel.

To much force and the brakes will be touchy to little force and you have to stand on them to get results........larger heavier tires, a heavier loaded vehicle all change the braking needs.........

Not trying to turn this into a tutorial on swapping brakes , as there is plenty of supporting info on-line , just pointing out the facts so that you can get the best performance from whatever components your using.

 

[Hedgehog]

This is what is going to happen, I'll figure out this end loop situation. Then I'll run it and see how things turn out.

This isn't a rocket science opportunity. ALL parts are Jeep parts. The new/old front disk brakes, the old drum brakes in the back, a brand new unassisted CJ Jeep master cylinder for a Disk/Drum system AND a new proportioning valve for a Disk/Drum system. Mentally where am I right now? If it works GREAT! If not crush the damned thing............right here right now I'm in an unusually bad place that makes me sick of all of it...........

 

[Hedgehog]

Goodness - man was I ever in a foul mood this afternoon. ....... Anyways, Harbor Freight came through once again. I did a search for reamers and sure enough a set of 11 popped right up. What the heck, I've needed reamers on several occasions so why not pick up a set. It took 3 different reamer sizes, adjusted several times per reamer to open the loop up, and I did cheat with my drill press set to it's slowest speed. The loop is the correct size and the plastic bushing fits perfectly. Another problem is behind me now and tarry99 you were right, it was easy. I'm finding out that with the proper tool, most jobs are easily done.

 

[Woolyworm]

Tahdah!


Wooly