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Old April 5th, 2021, 08:38 AM
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Jsully34 Jsully34 is offline
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Default brake master cylinder

We have a retired brush truck for our town that is a M715. Our union owns it, Hasn't ran in a while and they nominated me to get it running again. I got it to turn over and run with starting fluid but it seems the brake master is just toast? I would like to replace with the original but I see some posts with upgrades.

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Old April 5th, 2021, 09:30 AM
jhartings jhartings is offline
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Is the vacuum boost shot or the master cylinder?

I just did a upgrade from vacuum to hydroboost on my 69 Wagoneer and am super happy

Used this guy.
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Old April 5th, 2021, 01:30 PM
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Barrman Barrman is offline
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Welcome to the Zone.

The fuel system from the sock inside the tank, fuel pump and carb probably all need to be looked at and cleaned up.

The stock brake system works very well. Since this isn't your truck. Putting a stock replacement master cylinder on there might be the best route to take. Be warned that you will probably end up doing all 4 wheel cylinders as well.
Remember if you didn't build it you can't call it yours.

6.2 powered M715, 5 M1009's, M416, 2 M101's, 2 M105's, 3 M35's, M1007 6.5 turbo Suburban project called Cowdog.
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Old April 5th, 2021, 05:08 PM
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If the master cylinder is bad, then the wheel cylinders are probably also corroded. Get new master and wheel cylinders. I would go with the dual reservoir conversion using the corvette master cylinder as it works great without power assist. The original is a single reservoir. If the shoes are good and drums not tore up you can probably get away without having them turned.
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Old April 9th, 2021, 08:28 AM
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The decision to have these drums turned is one that shouldn't be taken lightly given their rarity, IMHO. Most every attempt I've seen made at turning a brake drum has ruined them through incompetence.
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Old April 9th, 2021, 03:20 PM
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kyken kyken is offline

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I did the corvette master and E350 wheel cylinder, have not had a problem since installed 10 yrs ago.
Thanks for all the help!
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