Bleeding brakes on ‘42

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runmikeyrun

Senior Member
Bleeding brakes on ‘42

Ok so I was able to replace a front brake hose on our 1942 Ford truck without a hitch today (thank you PB B’laster!) but I’m unsure how to bleed them. The bolt above the hose on the back side of the master cylinder looks like an adjuster of some sort, but not a bleeder.

Any help appreciated, thanks!
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Re: Bleeding brakes on ‘42

Do it the easy way. Get a hand pump oil can and fill it with brake fluid. Put a piece of rubber hose on the end. Put the other end on your bleeder. Open the bleeder and Pump fluid into the cylinder and up the brake line into the master cylinder. No mess, no muss, no fuss.
 
Re: Bleeding brakes on ‘42

Chris Haynes said:
Do it the easy way. Get a hand pump oil can and fill it with brake fluid. Put a piece of rubber hose on the end. Put the other end on your bleeder. Open the bleeder and Pump fluid into the cylinder and up the brake line into the master cylinder. No mess, no muss, no fuss.
Click to expand...
If this is what the bleeder screw looks like, " No mess, no muss, no fuss." is just wishful thinking.
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Re: Bleeding brakes on ‘42

I am guessing but you may have an original style bleeder with a small screw on top to block dirt from entering. If so remove the top screw, then loosed the hex under it to open the system for bleeding. Brake fluid will come out of the center opening that was blocked by the screw you removed. When finished tighten the hex to seal the system and reinstall the top screw. The car and light commercial bleeder looks like the photo below. The big truck has a larger bleeder of the same style.
 

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Last edited:
Re: Bleeding brakes on ‘42

You might do better to replace the bleed fittings with one that has a nub to take a bleeder pipe. If the bleed fittings are the early type, it could be that the cylinders are long overdue an overhaul or replacement.
 
Re: Bleeding brakes on ‘42

Yes, I have the original type and not the common type of bleeder. I’m not in a position to pull the wheels off the truck so I’m hoping a simple bleeding will be enough to get them to work. The brakes have been working pretty well so far.

Thanks for your help!

Mike


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Re: Bleeding brakes on ‘42

runmikeyrun said:
Yes, I have the original type and not the common type of bleeder. I’m not in a position to pull the wheels off the truck so I’m hoping a simple bleeding will be enough to get them to work. The brakes have been working pretty well so far.

Thanks for your help!

Mike


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Click to expand...
If you are talking about pulling the wheels off to replace the bleed screw, the screw can be replaced without removing the wheels.
 
Re: Bleeding brakes on ‘42

34PKUP said:
If you are talking about pulling the wheels off to replace the bleed screw, the screw can be replaced without removing the wheels.
Click to expand...



Nope, it was suggested that I replace the wheel cylinder if they are that old.


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Re: Bleeding brakes on ‘42

runmikeyrun said:
Ok so I was able to replace a front brake hose on our 1942 Ford truck without a hitch today (thank you PB B’laster!) but I’m unsure how to bleed them. The bolt above the hose on the back side of the master cylinder looks like an adjuster of some sort, but not a bleeder.

Any help appreciated, thanks!
67ffac9ca061d17c490d3896eabd39fb.jpg



Sent from my iPhone using Tapatalk
Click to expand...

I'd be careful with that RUSTED WHEEL !
 
Bleeding brakes on ‘42

So, will a standard bleeder screw with a nipple thread into the place the bolt is? Wondering if it’s the same thread pitch etc as a modern, sae bleeder


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Re: Bleeding brakes on ‘42

If the brake flid is that old in the truck you need to bleed the hole system and get that contaminated fluid out of there. Suck out all the old fluid from the master cylinder and fill it up. Start with the furthest wheel (Right rear) and bleed it until you see clean fluid coming out. Make sure not to let the master cylinder reservoir go dry. Next do the left rear. Then the right front and last the left front.

Since you only have a single system you want these hydraulics to be in perfect condition. As old as this is they really should be rebuilt from one end to the other. All new hoses and and a rebuilt master cylinder and wheel cylinders. If you don't do it you better keep an eye on that master cylinder reservoir level. Check it before you drive it "everytime" to make sure the fluid has not leaked out. Watch the backing plates for signs of leakage, like the wrinkled paint in your photo. Brake fluid eats paint.

Its not that big a deal to pull the rear drums if they have floating axles. Its just a little messier!
 
Re: Bleeding brakes on ‘42

runmikeyrun said:
So, will a standard bleeder screw with a nipple thread into the place the bolt is? Wondering if it’s the same thread pitch etc as a modern, sae bleeder


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Click to expand...

Yes, but as this is a truck part I can't advise on what thread it is.
 
Re: Bleeding brakes on ‘42

I’m gonna pull it out Monday am and match it to my thread pitch gauge. Has to be a standard item.


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