Master cylinder fitting leak

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Master cylinder fitting leak

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Master cylinder fitting leak

Postby Cav Trooper » March 13th, 2019, 6:40 pm

I have a problem with the fitting on the master cylinder of my A2. I've checked the brake line fitting and it is tight and does not appear to leak, the banjo bolt and seal don't seem to leak either and I've snugged that up just to make sure. What appears to leak is the pipe plug and the left side of the brass fitting. I've tightened it last fall a couple of times and it looked like it had stopped leaking but, I just uncovered the old girl and sure enough there is a wet spot from the master cylinder and feeling the bottom of the fitting it is wet again. Silicone brake fluid and brakes feel great. I've orderd a 4 point socket so I can get a full grip on the plug but I'm afraid to torque on it too much. Is there a sealant I can use with the Silicone brake fluid? I hate to open the system up and drain to seal but the drip is irritating.

CT
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Re: Master cylinder fitting leak

Postby Surveyor » March 13th, 2019, 9:45 pm

Was having similar problem. Thought it was the copper washers and turns out it was the brake pressure switch that I believe is replaced with a plug on your later a2. It just needed a slight nudge to tighten and stop the leak. That being said, I have never used a sealant on a brake line but you may want to try something like Seal-all. http://eclecticproducts.com/seal-all.html It dries clear and stays rubbery so easily removed if need arises.... course safety would be my main concern when doing anything with brakes.

If you do have to replace the plug and open it up and if I read Geoge's instructions correctly, you could push down on the brake pedal and open the front driver bleed screw to allow the pedal all the way past the fluid opening in the master cylinder. Close the bleeder but keep the pedal pressed down so the master cylinder won't drain. Replace plug and I assume probably the washer that would go with it. Tighten and then you should just need to bleed the front driver side. Suggest 2nd opinion from RIck or other expert before attempting however. I'm not a mechanic by any means but have stayed in a Holiday Inn Express numerous times.

if you only need to replace one cilinder or a hose
i do take the bleeder a litle open at tad side and pusch the pedal in
with a block of wood or a hammer i let stay the pedal pressed down
the master cillinder wil not go empty and the air is not coming to in
now you can repair the brake and you have only bleed tad wheel

save`s a lot of work - george
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Re: Master cylinder fitting leak

Postby Cav Trooper » March 13th, 2019, 10:39 pm

Fil and Rick indicated last year when I found the initial leak that that plug is a pipe thread. I'm with you as far as messing with brakes and introducing a sealant to the system. If I crack the system open to use a sealant, I believe I'll have to drain the MC of all fluid and try to clean the threads of any brake fluid in the brass fitting and pipe plug to get the sealant to stick. I may have to replace the fitting and plug with a new one just so there is no brake fluid contamination to prevent the sealant from working. After that, replacing the banjo bolt seal also. That all depends on whether I can tighten the plug enough to stop the leak without more work. That said, I'll wait to see if the experts respond and I get the pipe plug socket I ordered before trying to wrench the plug anymore.
I also found a antifreeze leak at the heater. Antifreeze leak appeared while I was letting the engine idle and warm up after the winter's nap. I can't tell where it's leaking, I'm hoping at one of the heater hoses but they felt dry. I just turned the shutoff valves off and won't worry about it much since I don't run it with the heater on anyway. Just more tinkering. Option is some stop leak but I hate that bandaid.

Thanks for the reply and input.
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Re: Master cylinder fitting leak

Postby rickf » March 14th, 2019, 8:07 am

I think it is probably the pipe plug for the brake switch and you have a couple options. If it is a steel pipe plug you can replace it with a brass plug and that should seal a little better or you can take the steel one out and put some teflon tape on the threads and put it back in. Just be sure that the tape is only on the threads and not past the end of the plug. The teflon will not react with the brake fluid. Brake fluid will not react with most sealants, you just need to keep the sea;ants on the threads and out of the system so it does not get into the master cylinder and gum up a port. And if you push the pedal down just till you start to fell a little pressure and block it there with a stick against the seat you can remove the plug and you will only get a little leakage as the pressure bleeds off and then no more should come out after that. once the plug is back in then release the pedal and check the brakes. If anything you may need to bleed one rear brake to get any air out of that line but there really should not be any in there.
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Re: Master cylinder fitting leak

Postby Cav Trooper » March 14th, 2019, 8:06 pm

I will get a brass pipe plug and try that. I really appreciate your info on the brake pedal procedure. I've never tried it before, just break the system open and bleed, bleed, bleed. I hate bleeding brakes and it doesn't get any better at 71. I like good old fashioned short cuts that save me time and work and get the job done.
Thanks again Rick and all.
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Re: Master cylinder fitting leak

Postby Cav Trooper » March 23rd, 2019, 9:29 am

I got a brass pipe plug and a correct square drive socket, now for warmer weather to install and try to find someone to help if I need to bleed the brakes.
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Re: Master cylinder fitting leak

Postby m75 » March 23rd, 2019, 11:47 am

When I was wrapping up my brake MC and line replacement work, I found that re-using the copper crush washer at the banjo fitting was not the best idea, based on the amount of fluid that I immediately lost. I locally sourced similar replacement washers, but they did not allow for adequate sealing either, with the same dripping result.

I sourced from Red River and received the NOS items, which, of course, fit perfectly and more importantly, sealed the banjo fitting and removed the leak.

I had no issues with the pipe plug itself, so maybe I dodged that bullet?
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Re: Master cylinder fitting leak

Postby Cav Trooper » March 26th, 2019, 9:58 pm

Thanks again, I'll see it Red River still has banjo fitting washers. Can I buy just the seal or do I have to buy the banjo bolt too?
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Re: Master cylinder fitting leak

Postby m75 » March 27th, 2019, 12:05 pm

I was able to purchase just the copper washers.
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Re: Master cylinder fitting leak

Postby Cav Trooper » March 29th, 2019, 12:07 am

I just called Red River this afternoon. I evidently got their last set of new washers. They said they had used ones and I did not want used so the guy check the pn book and found he had one of each NOS. On the way.
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Re: Master cylinder fitting leak

Postby D Pizzoferrato » March 29th, 2019, 7:13 am

I always got these at NAPA in boxes of 10. Should be a common brake part.
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Re: Master cylinder fitting leak

Postby Surveyor » March 29th, 2019, 8:30 am

As per D's post... https://www.napaonline.com/en/search?te ... rm-allprod

Just need to compare for size(s). Original ones on top and bottom are different but one size may work for both since it works for D. If you get a part number we should add it to the wiki.
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Re: Master cylinder fitting leak

Postby rickf » March 29th, 2019, 8:34 am

The problem I have found with NAPA stuff (and the reason I no longer go there) is that they are not the original company they used to be. Everything they have now is Chinese garbage. I have gotten some of those brake washers from there for my Dodge truck and they were far to hard to seal anything. I ended up annealing them to make them soft and they worked after that but looking at the box and sure enough, made in China.
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Re: Master cylinder fitting leak

Postby svramselaar » March 29th, 2019, 9:04 am

hi

i use for those difficult places new aluminium rings they are softer
a copper ring wil hardend wen they age at the box
you can soften them up
heat them red glow and drop it at cold water

george
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Re: Master cylinder fitting leak

Postby rickf » March 29th, 2019, 3:40 pm

I always heated them and let them cool naturally. Won't a water quench harden them just like steel? Dammit George! Now I am going to have to go out and do a bunch of heating and cooling experiments on copper washers! :roll: :roll: :roll: :lol: :lol: :lol:
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AN/TSQ-114A Trailblazer- Gone
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