1971 Brake Problems

VasiliBrown

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I have 4 wheel manual drum brakes. I replaced all wheel cylinders and wasn't getting fluid to them. Car has been sitting since 2002 so I replaced the master cylinder as well, which was good since it wasn't pumping any fluid. However I'm still getting zero fluid to the wheel cylinders. I was going to replace the distribution blocks however someone else suggested replacing the lines. I wouldn't think that one bad line would cause no fluid would make it to any wheel. What do you guys suggest I do?

 

kcmash

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I have 4 wheel manual drum brakes. I replaced all wheel cylinders and wasn't getting fluid to them. Car has been sitting since 2002 so I replaced the master cylinder as well, which was good since it wasn't pumping any fluid. However I'm still getting zero fluid to the wheel cylinders. I was going to replace the distribution blocks however someone else suggested replacing the lines. I wouldn't think that one bad line would cause no fluid would make it to any wheel. What do you guys suggest I do?
I suggest you flush the system.

Not sure what power bleed systems are out there, but I suggest disconnecting at the distribution valve first, to see if you can blow fluid through there.  If that is clear, I would disconnect at the differential, and the front wheel cylinders and pump a bunch of fluid through there to flush the system.  If you are getting rust out of any of those areas, see if you can flush it clean, but that probably means it time for new lines.

From my experience, I suggest going with non-stainless lines.

kcmash

 
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Pastel Blue

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I'm going through this issue at the present time on my '73 vert. I refurbished the complete entire underneath of the car, replacing parts as necessary but keeping as much original as possible. I did not change the brake lines except for new rubber lines at the front brake discs and the rear rubber brake distribution line at the rear differential (my fault on that one, as I put too much heat on the distribution block and blew the rubber line trying to get the rear diff. brake lines off).

I did not change out the master cylinder or the brake booster... I went to bleed the brakes yesterday and was barely getting fluid to the rear passenger drum. The master cylinder also started leaking at the usual point under the unit on the brake booster. Took the master cylinder off and it was toast... should have known better and changed it out originally. I am now also removing the brake booster as well and will have both original pieces rebuilt and then I should be good to go on the brake system. 

Your comment about not getting any fluid is one of two issues;  faulty master cylinder or a blocked line, more likely the distribution block at the master cylinder. 

Process of elimination is required here... Good luck.

 
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Did you prime the new master cylinder before putting it on the car? Very important step.

Otherwise as kcmash suggested.

Why not ditch the front drums and install a disc conversion. For my 71 drum/drum non power brake Mach 1, I purchased SSBC's Kelsey-Hayes style 4 piston kit which fit directly on the 71 drum spindles and a very easy swap. I also ditched the old brake lines and went with all stainless while at it. I drove for several years without a power booster, which I installed a couple of years ago now, but that is major work. The so called direct fit power booster kits do not work if you car has shock tower braces. besides, they use the existing push-rod pin that is 2" too high for correct pressure.

Hope that helps

Geoff.

..........And as Pastel Blue suggested

 
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NOT A T5

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I used one of those Mightyvac vacuum pumps and it worked pretty well. And oh boy a lot of crap came out of my old lines many years ago but I'm switching over to SS lines in the near future. They're just waiting until all the welding gets done.

 
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SVO2SCJ

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After SEEING the inside of my 1969 valve and rebuilding easily HERE https://www.musclecarresearch.com/valve-kit-kh I would suggest the $20 and effort . We now redo all hydraulics, though not big on replacing lines in my restorations. (My cars are from AZ, lines clean up with phosphate and I NEVER USE STAINLESS STEEL (nothing but hard work to seal) IMO.

Mark

P.S. The kit I linked isn't for a drum drum - but I wanted to get you to Scott's site and you can click on instructions to SEE how to do it. (Again EASY)

 

libram

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I would agree your best option is troubleshooting. Use air if you must or pressurized fluid to flush and it should become pretty obvious where any blockage is located. Basically become the pump/booster.

 
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After SEEING the inside of my 1969 valve and rebuilding easily HERE  https://www.musclecarresearch.com/valve-kit-kh  I would suggest the $20 and effort . We now redo all hydraulics, though not big on replacing lines in my restorations.  (My cars are from AZ, lines clean up with phosphate and I NEVER USE STAINLESS STEEL (nothing but hard work to seal) IMO.

Mark

P.S.  The kit I linked isn't for a drum drum - but I wanted to get you to Scott's site and you can click on instructions to SEE how to do it.  (Again EASY)
 Mark, Now that is a kit that I'm sure many do not know about. Read many times from guys having trouble finding a correct, i.e. suitable proportioning valve for their application. I certainly was not aware of it.

I my case, I swapped out the front drums for discs and that kit came with a separate rear brake bias valve. And YES I did use stainless lines throughout without ANY issues at all sealing them. I am convinced that why people have trouble is because they don't have or use the correct LINE wrenches and a well fitting back-up wrench. Old or worn out tools will invariably result in problems imo.

Also, my car was from California. It was a totally rust free car, but even then, the old brake lines I took out were full of RUST. Brake fluid absorbs moisture and that moisture will cause rust. I have had a total brake failure on my previous  72 Mach 1. The line that BLEW was because of rust inside. That my friend was a situation that could have killed me had I been driving faster.  Fortunately I saved it without hitting anything or anyone. Why take the chance with old lines that LOOK great on the OUTSIDE when it's the INSIDE you need to worry about. If you have a mental issue with SS lines, there are alternative materials available that will last the life of the car and yours as well.

That's just MY opinion, I'm not a mechanic, I just know what I know. Take it or leave it!

Geoff.

 

VasiliBrown

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I was able to get a vacuum pump on there and suck fluid through the lines. turned out to just be a massive air bubble

 
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I was able to get a vacuum pump on there and suck fluid through the lines. turned out to just be a massive air bubble
That's good news, but please don't overlook the condition of old lines. They are not that hard to replace especially if you buy pre-formed. Also the rubber hoses are  likely in need of replacing. Trust me, a total brake failure is an experience you DON"T want.

Geoff.

 

71 gbvert

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Agree with Geoff - replace the brake hoses. Cheap insurance.

 

Ron Tanzi

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We use rolls of nickel/copper alloy line at work. It bends and flares very easily. We buy 50 foot spools of it in 3/16" and 1/4' and make up our lines that we need. I flush the brake fluid on my cars including the Mustang every 2 years. I use a vacuum pump setup that I built from components (vacuum pump and a beaker) sourced from my parents former medical lab. It works really well and pulls more vacuum (20" hg) than anything you can buy out there for the purpose. I use it for flushing/bleeding the brakes for my home clients as well.

Ron

 
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One safety check I do before I take car out is to stand on the brake pedal with both feet so if there is a weak point in a line or cylinder it will blow in the garage not going down the road. The pressures are high in there but the surface area in the lines is tiny for a reason.

David

 
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