Master cylinder conversion help needed

Dennis,

Mine was both riveted by a rivet on each side of the shaft and also welded to the frame. Looked like factory welds that were hidden by grime and dirt. After drilling grinding the heads off the rivets and drilling up through the body of the rivet, I needed to use a cut-off wheel to cut through the weld. Then I used a 3 lb mini-sledge to alleviate the frustation from all the previous work.

HTH.

 

I'm afraid the clutch tube bracket is welded as well. I'll put the wire wheel to it tonight and see what I can find.

 

Removing those rivets is a royal pain.

Once the heads are gone you can punch the rivet back through.

I sounds so simple, but is isn't. Add to that the fact that you really cant get a good swing at it.

A couple of things..

It may look as if you have the entire head cut off, but that can be misleading. A wire brush on the end of a drill can polish it up so you can see. Interestingly, once you get the entire head of the rivet off and wire brush it, you can actually see a circular outline of the rivet. Unless you see this circle, chances are that you have not removed the entire head of the rivet.

I then center punched and drilled a small hole in the center of the rivet. I gradually worked up the drill size to near the size of the rivet. At that point a punch was able to take it out.

It was not easy and not fun. I have removed f-134 motor mounts, the clutch pivot bracket and bumpers this way, and I avoid it any time I can.

I don't remember a weld on the clutch control mount I removed -- there may have been one, but I don't remember one.

In order to protect my eyes during this I always wear one of those face shields that swing down like a welder's helmet. Getting metal chips in the eyes is bad form.

 

I used a 1/4" drill bit to remove the center of the rivet on mine. then a air chisel to peel the head off the rivet. also i used a hand chisel as a wedge to help the bracket seperate from the frame.

 

Ok, I got the rivets out. Out of curiosity, I put the new bracket in place to see if it would fit before removing the plate. It did! I then put all of the bolts in place to see if it would line up... It did!

Next question, do I have to remove the support plate if everything fits? I don't see why I would have to. I'd like to go and get long bolts to go through the frame and be done with it. Can I?

I do have to shorten the plunger rod, it's way too long. That shouldn't be too difficult, though.

Thanks!

 

Hmmm, I was thinking of doing this to my '56. Sounds like I'd better do it while I've got it stripped to the frame, as part of the re-assembly. What all comes in Herm's kit? Everything you need, or is there scrounging involved?

 

Dennis,
On my '70 the outer (from centerline) part of the mounting flange set inside the frame rail. The body was flush w/ the boxed part of the rail that the Ross box was mounted to IIRC. I'll check in the morning to be sure. I don't know if it would be different for a '56 or not. I guess what matters is where it lines up to your brake pedal, if it ain't touching nothing no harm no foul.:v6:

 

Ron- Do it with the tub off! I wish mine were right now. You get everything you need. Plan on some degree of 'making things work'. Oh-keep the plunger boot from your old m/c. You need to re-use it.

granny- it's not touching anything. The only mod is shortening the plunger rod. I think I'm good...

 

Sounds like a hard fought job well done. Way to go Dennis.8) :v6:

 

Yep, existing plates in place and it fit. The instructions said it wouldn't but it did. I need to get longer bolts to go through the frame, but I'd rather do that then chance damaging the frame while removing the support plates

 

Great info. I am planning on doing this mod to the DJ while I have the tub off, along with 11" brakes. Thanks for the vicarious experience!

 

If you do decide to remove the bracket, you can get an M38 / M38A1 bracket which has bushings inside and helps to eliminate pedal wobble.

It will have one extra hole on the side of the frame to drill (M vehicles have three bolts holding that bracket on)

 

The saga continues...

With the bracket bolted in, the new m/c hit the plate that held the old m/c. Spent some quality time with the die grinder and that issue is solved. On to the next problem...

The new m/c isn't in the same position as the old one. It is moved to the rear exactly 1 1/2", which makes the plunger rod too long. Ofcourse, there isn't that much adjustment in the rod, so I got the tap and die set out and added another 1" of thread to the adjustment bolt. I had to cut the adjustment bolt by 1" as well. It now works just fine. On to the next issue...

Removing the old brake switch...should be easy, right? It came right off, but the screws for the wires are so badly rusted and corroded, that they will not come out. Wonderful Ok, Krage has new switches for 3.99, no biggie. I'll order one on Monday.

Next issue... the m/c is threaded 1 size bigger than the brake line fittings. I'll go get some adapters today and solve that problem. While I'm there, I'll pick up a "T" and plumb in the old brake light switch so that is done.

Word to the wise on this. Although I believe this conversion to be worthwhile, don't plan on doing it in 1 day if the tub is not off of the frame. This has been the biggest PIA project I've done so far. The only thing that I'm looking forward to when done is having the knowledge to share with the next poor guy that wants to do this upgrade.

Back to the garage...

 

Do a good write up and where's the darn pictures???

 

I put 6 hrs in today and finally got it done...at least I thought.

It turns out the the bracket supplied in the kit stops the arm of the brake pedal from traveling the proper distance SOOOOOOOO, I took the tranny cover off and decided to work from the top. got the die grinder and took out quite a bit of material. That works now. While I was there I went ahead and welded the top of the braket to the frame, just like the instructions recommended. That really stiffened things up. Good move!

Another fun thing was the chevy bellhousing is surprisingly close to the frame... so close, this almost didn't happen. The problem is the m/c is tapped for 5/16 fittings and the jeep is plumbed in 3/16. The adapters make it stick out too far and the bellhousing is in the way. Back to the parts store... It is now plumbed in 5/16 and adapted down to 3/16 at the "T"'s. WEEEEEEEEEEE

The only good thing that happened was the local parts store had the brake light switch in stock 8)

Put it all back together. whew... that was tough tearing it down for the 4TH time. Dan and I bled the system again. all of the air is out now so we put the JEEP back together. I take it for a test drive and all goes well. Let it sit in the driveway while cleaning up the mess and, to my disbelief, there is a lovely puddle of brake fluid right under the m/c. I crawl back under it (not an easy task for this fat guy) and it's not coming from the fittings. I look a little further and it wet on the back side of the m/c . Pull it back into the garage and guess what :? I have to tear it apart one more time. It seams that removing the old m/c support bracket still doesn't leave you with enough room to properly seat the top of the new m/c . I have to trim the frame back and this time, I will take enough out of it. I stopped from pure frustration. I'll go at it again one night this week. I chose not to take pictures for fear of throwing the camera. I will do a complete, photo free, write up of this adventure. Hopefully, it will save someone else from tearing theirs down 5 times

I need