Thread: Master Cylinder?

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Well I was really inspired after the Richmond Nationals and all those high quality cars so I spent most of the day working on my '29. In particular I have been having a lot of frustration with my brake lines. It took a LOT of pumping of the pedal and wasting a lot of fluid but I finally got fluid to come out of all the wheels with the cocks open. Then I started to eliminate the leaks. Due to a good chat with the guy from the Flatlander shop in Norfolk at the Richmond show (he displayed a really neat 3-window 'glass body all set up ready for interior and paint and had the same kind of thru-frame front brake lines I got from Speedway) I tried using teflon tape. Anyway he advised a full 3 1/2 wraps of teflon tape on leaky fittings and I tried that today. I was doing fine eliminating one leak after another and starting to get slightly optimistic after a long frustration with the brake lines and finally I got rid of all the leaks but one. The problem is that I have what I think is a Corvette dual chamber master cylinder and it has FOUR outlet holes of which I only need two and the other two are supposed to be plugged by threaded bungs. I sealed one off with teflon tape but the other still leaks after three tries with successively more tape each time. Now I have totally rounded out the shallow Allen-wrench hole in the bung and it is in so tight now I cannot get it out or tighten it and it still weeps a little when I pump the brake pedal. My last resort may have to be to pull out the whole MC and chuck it up in my 6" vise and chisel out the bung or perhaps tighten it by applying a small cold chisel at an angle along the edge to tighten it more. The problem is I will have to loosen several other fittings to get the MC out and maybe have problems getting them sealed again. How about it out there, what can be done to work with a rounded out Allen wrench hole? On other threads some of you have divulged some really neat tricks for other problems. What about a rounded out Allen wrench socket hole. I am considering sawing off an "easy-out" where the diameter will be close to the size of the rounded Allen socket, which is disgustingly shallow. Maybe an easy-out will work but then that is only getting it out, how to tighten it later? This is the final leak in my brake system and if I can get this sealed I can finally move on to the next problem on my chassis! Suggestions?

Don Shillady
Retired Scientist/teen rodder

use a torx socket the next size bigger than the hole. may have to grind it to a point to get it started and drive it in or try the easy out like you said.

ps -are you going to the Super Chevy Show next mo. don ?

Well in order to inject some raisins into the tastless dough of existence we sometimes have to use "current" events and be grapefull for the hard work of event organizers! I can't promise to go to that meet, it is it Lynchburg? Why not give some details about time and place here so maybe some others will learn about it too. Although the NSRA event was not specifically for Chevys, I'll bet over 90% of the engines were Chevys! The NSRA formula is close to a historical development of rodding with mostly Ford or Ford replica bodies with mostly SBC engines, but there were some early Willys, some hemis and some early Chevy bodies. Still most were (fine by me) early Ford type bodies with Chevy engines. It would be neat to meet some folks from this (International) Forum, but I would rather go in my car but that may be more than a year away. By the way tell me more about the totx socket.

Don Shillady
Retired Scientist/teen rodder

Originally posted by Don Shillady
Well in order to inject some raisins into the tastless dough of existence we sometimes have to use "current" events and be grapefull for the hard work of event organizers! I can't promise to go to that meet, it is it Lynchburg? Why not give some details about time and place here so maybe some others will learn about it too. Although the NSRA event was not specifically for Chevys, I'll bet over 90% of the engines were Chevys! The NSRA formula is close to a historical development of rodding with mostly Ford or Ford replica bodies with mostly SBC engines, but there were some early Willys, some hemis and some early Chevy bodies. Still most were (fine by me) early Ford type bodies with Chevy engines. It would be neat to meet some folks from this (International) Forum, but I would rather go in my car but that may be more than a year away.

Don Shillady
Retired Scientist/teen rodder

http://www.clubhotrod.com/forums/sho...per+chevy+show

i posted this last week don, didnt get 1 reply.


http://www.superchevyshow.com/

Don, I guess I've never used a 4-outlet cylinder. The last 'Vette cylinder I used on the T was a 2-outlet model.

I think you're setting yourself up for a problem down the road with this teflon tape business. If you have 2 outlets for the rear, run a flared line off each one and join them together with a tee, then run one line to the rear. Do the same with the 2 front lines.

Brake systems will generate in excess of 1,000 p.s.i. and I don't think teflon tape is the hot tip. Everything was made to seal with double flares.

Tech1, thanks for your expertise, I wondered about the tape myself. The funny thing is that the right side front disk brake connection sealed up right away but I gave up on the left side after many tries to seal without tape and then I bought another of the thru pipes from Speedway and that leaks too. I also bought another fitting to go into the pipe but that leaked too, although slightly so I went back to the old fitting which had already deformed slightly to the existing double flares and that seals OK with a little wrench action. On the thru pipes there is no shoulder to seal to, just a pipe thread. The tech guy at Speedway said to use pipe sealer so I tried liquid teflon sealer but as you say the pressure just squeezed the teflon paste out of the threads. So far only teflon tape has sealed the left front while the right front works fine. I guess I can keep on buying fittings until one seals without the tape? Anyway on the MC it is too late tonight to snap a picture and it is in a tight place but maybe tomorrow I will take a picture for DennyW. At this point I regret using the stainless tubing and the AN3 fittings and wish I had just used standard steel tubing. The moral is that while a pro may do a beautiful job as shown on some other posts, stainless tubing is a tough learning curve for amateurs. I may have to scrap the whole system becasuse as Tech1 says the brake system is Oh so important!

lts10, I don't know how I missed this notice since I am in Auto-Zone at least three times a week but maybe we gave it some additional publicity now.

Don Shillady
Retired Scientist/teen rodder

Originally posted by Don Shillady
Tech1, thanks for your expertise, I wondered about the tape myself. The funny thing is that the right side front disk brake connection sealed up right away but I gave up on the left side after many tries to seal without tape and then I bought another of the thru pipes from Speedway and that leaks too. I also bought another fitting to go into the pipe but that leaked too, although slightly so I went back to the old fitting which had already deformed slightly to the existing double flares and that seals OK with a little wrench action. On the thru pipes there is no shoulder to seal to, just a pipe thread. The tech guy at Speedway said to use pipe sealer so I tried liquid teflon sealer but as you say the pressure just squeezed the teflon paste out of the threads. So far only teflon tape has sealed the left front while the right front works fine. I guess I can keep on buying fittings until one seals without the tape? Anyway on the MC it is too late tonight to snap a picture and it is in a tight place but maybe tomorrow I will take a picture for DennyW. At this point I regret using the stainless tubing and the AN3 fittings and wish I had just used standard steel tubing. The moral is that while a pro may do a beautiful job as shown on some other posts, stainless tubing is a tough learning curve for amateurs. I may have to scrap the whole system becasuse as Tech1 says the brake system is Oh so important!

lts10, I don't know how I missed this notice since I am in Auto-Zone at least three times a week but maybe we gave it some additional publicity now.


Don Shillady
Retired Scientist/teen rodder

my brother called me yesterday and ask me if i wanted to go, i told him i would let him know. its a big show. if you'er going let me know. riverhorse goes every yr.

Just a question Don. Did you use a 37 degree flare or 45 degree?

Hey Bob, I too think this may be a flaring tool issue. I have never had as much problem as Don is refering to. I would really suggest you move away from any form of sealing tape on a flared connection. The thread is only to apply pressure to the double flared end. The thread itself does NOT seal. Take a look inside the fittings to see if the nipple that the flare pushes onto is deformed. I like the idea of using a tee peice to bring your 4 way together. Also I would never use brass anywhere in a brake system, stick to steel only unions. Good luck.
Andy.

hearing this i must consiter myself lucky, i just filled the system in my roadster this last weekend and had 1 small seep in the rear T-fitting, i just didnt tighten it well, i also used the an-3 fittings but with steel lines it all worked well.. and a very nice pedal to boot..... hope the heck to fire it up next month...(i have to finish the stinking wiring)

Don----bad on you. Should never use teflon tape on brake lines. The seal does not happen at the threaded interface. The seal happens as a result of the flared section of brake line being forced onto a mating cone in the fitting which the brakeline is being attached to. All the thread does is provide a mechanical force to hold the male cone on the fitting and the female flare on the brakeline together under high pressure. I would suggest that either you used a flaring tool with the wrong angle, or used incorrect fittings.-----there should never ever be fluid getting past the flared area to the threaded area.

HEY BRIAN, have you got me iggied mate?
Looks like great minds think alike hey....perhaps cause we both have A's.

Andy

Gherkin350 ---No, I don't have you iggied. I am backing you up, thats all. Don and I have been sharing information ever since we started building our rods, thats all. Your diagnosis was right on.

Don, here is my experience which sounds similar to yours. I bought the neat stainless tubing, the AN3 fittings and one of the hydraulic forming tools that makes the flare.

Set out building brake lines for a 4 wheel disc setup. Looked like a million bucks but leaked like a Democrat Senator keeping a secret. About half of the fittings leaked. Tried multiple fittings..... with no improvement.

Used a magnifier to look at each joint and found that the problem was the stainless. Andy and others are right....NO teflon tape or sealer, the interference of the cone on the fitting makes the seal. A 45 degree fitting actually has one side cut at a slightly different angle.....just like a engine valve seat. The seal is made by a narrow contact circle just like the engine valve. If you look at your tee or other block where the tube contacts, you might see a depressed ring....chances are that these seats will leak next time that you try to install a tube.

My solution? I went an bought lengths of regular steel tubine and tossed the stainless. Every leak stopped. Doesnt look as cool but you can polish it and then apply a clear coat.

mike in tucson

Thats cool Brian as long as the good info gets to the person asking the question who cares how they get it.

Don, hows those photos comin along?

Andy.