Bleeding Brake lines on a 1939 Ford Deluxe

[Ramblin Reck]

We have gone thru 2 Quarts of DOT 3 brake fluid trying to get the brakes bled but no luck.

We had a leak in one of the cylinders but we fixed that.

All brake lines are new, new master cylinder and new wheel cylinders.

We have fluid in the lines out to the bleeder valves.

Only about a thimble of fluid goes into the master cylinder and quickly overflows out of the fill hole.


We believe that if we had a threaded funnel so that constant brake fluid would be keeping the master filled would help. Does such a tool exist?



All helpful comments will be appreciated. Thanks

[1931 flamingo]

Where did the 2 quarts go??
Make sure the rod that goes into the m/cyl from the brake pedal has clearance. Is this an orig type m/cyl or a later dual port (mustang?). Probably start at the LR wheel cyl, the RR, FR and last LF. FWIW
PAul in CT

[19Fordy]

1931 makes a good point. Find out where that fluid going?
Read all this and then do a Fordbarn "Search" on Bleeding brakes".

Folks on Fordbarn have reported on the same problem and the cause was found to be improperly reproduction manufactured wheel cylinders.

Read about it here:
https://www.fordbarn.com/forum/showt...heel+cylinders

[Ggmac]

Are all bleeders releasing fluid when pressure bleed ? New shoes or old ? Double inverted flares on brake lines ? If you bleed your master dry , you must start over . This time bleed a wheel then recheck your master . Do not fill your master too the top AND install the cap tightly . I had a vacuum ( guessing? ) that happened to me recently when doing so .

[jayvee34]

If you did not bench bleed the master cylinder before putting it on the car and the master cylinder is not setting level there is air trapped in it and you will not be able to bleed the
wheel cylinder's with air trapped in the master cylinder. If what is mentioned here is correct, remove the master cylinder, put it level in a vise to hold it and bleed it.

[Ramblin Reck]

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Originally Posted by 1931 flamingo

Where did the 2 quarts go??
Make sure the rod that goes into the m/cyl from the brake pedal has clearance. Is this an orig type m/cyl or a later dual port (mustang?). Probably start at the LR wheel cyl, the RR, FR and last LF. FWIW
PAul in CT

Onto the floor, wasted.

Original type m/cyl

[Ramblin Reck]

Originally Posted by jayvee34

If you did not bench bleed the master cylinder before putting it on the car and the master cylinder is not setting level there is air trapped in it and you will not be able to bleed the
wheel cylinder's with air trapped in the master cylinder. If what is mentioned here is correct, remove the master cylinder, put it level in a vise to hold it and bleed it.

No we did not bench bleed the m/cyl before installing
We disconnected the rear lines and got some air out of the m/cyl while still installed on car

[jayvee34]

Originally Posted by Ramblin Reck

No we did not bench bleed the m/cyl before installing
We disconnected the rear lines and got some air out of the m/cyl while still installed on car

Bob, If it is not level in the car there still could be some air in there. Me, I would
still take it out and bench bleed it as mentioned. Call me if I can be of further
help.

[Mart]

I used a vacuum bleed setup on my 32. I put red grease around the bleeders and it worked pretty well. The only ones I had a problem with were ones where the fitting wasn't tight. It worked well for me as I was doing it singlehandedly.
Mart.

[Ramblin Reck]

Originally Posted by jayvee34

If you did not bench bleed the master cylinder before putting it on the car and the master cylinder is not setting level there is air trapped in it and you will not be able to bleed the
wheel cylinder's with air trapped in the master cylinder. If what is mentioned here is correct, remove the master cylinder, put it level in a vise to hold it and bleed it.

Thanks John When Ron returns to help we will correctly bleed the Master/cyl. by taking it out and putting in a vise and then using old brake line or clear tubing. Additionally we will also keep the pedal from traveling all the way down, keeping it 1" to 1.5" off the floor. I believe these are the key points you made in our phone con.

[FortyNiner]

I'm curious, how will keeping the pedal from bottoming out help?

[paul2748]

Do you put the cap on the master before you bleed the cylinders? You can push the fluid out of the hole if you don't.


Never had to bench bleed a single cylinder master. Always pushed the pedal all the way down to the floor too. never a problem

[wga]

Ramblin, used a hand held vac bleeder, this is the one I used on my 49.
https://www.summitracing.com/parts/anm-cp7835
On a stock MC you might get away without bench bleeding. If doing the brake pedal bleed, be sure all the wheel cylinder fittings can be opened easily. Use a flare nut wrench.
I bleed my brakes on my own now with no issues with this bleeder tool.

[jayvee34]

Originally Posted by FortyNiner

I'm curious, how will keeping the pedal from bottoming out help?

Eliminates compressing the spring completely and any possibility of damaging
the plunger in the master cylinder. When the brake system is working properly
the pedal is never pushed to the floor during operation.
Not a requirement, but IMO a good practice to not damage the master cylinder.

With the one person vacuum bleeding system, no need to push the brake pedal.

[Brian]

'We believe that if we had a threaded funnel so that constant brake fluid would be keeping the master filled would help. Does such a tool exist'?
Yes, sort of...it is possible to mount a remote reservoir on firewall or any convenient place which 'adds' head to the level in m/c. I installed one on my 35 when I converted to hydraulics.
And...I still had major issues bleeding the brakes. Like you, everything was new....just 'cause it's new doesn't necessarily mean it's any good...I couldn't see any leaks anywhere. Ultimately, by a process of elimination, I purchased some new seals [PBR a known brand], and upon removing the existing ones out of the 'new' cylinders, it was apparent the PBR seals were at least 1 mm [.040"] bigger in diameter. I 'think' even though there was no apparent leaks of fluid, that when pressure was released in the system [foot taken off the brake pedal] air could get past the seal[s]. I ended up getting all the [new] cylinders sleeved in stainless and re-kitted with quality parts, brakes bled up spot on and are now excellent in all respects.

[FortyNiner]

Originally Posted by paul2748

Never had to bench bleed a single cylinder master. Always pushed the pedal all the way down to the floor too. never a problem

X2.

When I have bench bled a single chamber master it didn't seem to change anything about bleeding the system.

[bob from red oak]

harbor Freight sells an inexpensive self bleeder with a small bottle that fits on the master cylinder and allows you keep it full while bleeding. No air gets into the master as long as you keep fluid in the bottle.

[Ramblin Reck]

Originally Posted by bob from red oak

harbor Freight sells an inexpensive self bleeder with a small bottle that fits on the master cylinder and allows you keep it full while bleeding. No air gets into the master as long as you keep fluid in the bottle.

I bought this product and although it may not work on the 1939 MC it did spawn a good idea that may solve a problem we have had. The problem was that by using a funnel only a small amount of DOT3 would get into the MC each time I poured it into the funnel. So we made a reservoir system like the Harbor Freight Bottle uses for more modern cars.The 1939 MC Plug has fine threads and easily screws into a 5/8" fine thread nut.


A Flange Adapter
3/8"FL x 1/2"FIP bought from ACE Hardware along with a 1/2" Steel Pipe Nipple, which are common items at Ace completes the temporary reservoir which can then be used to keep a constant supply of DOT3 fluid going into the MC without having to keep pouring it in and wasting the fluid. Couple this with either a brake pumping action or using an air compressor to suck the fluid to the wheel cylinders and brake lines should fill up quickly. It is the same concept that this system uses. I will report back on the success of this system when my brake mechanic is able to get away from his other duties. Hopefully I can share a picture of our invention which I will try to do now......... No need for a picture as the funnel I "Invented" is not necessary. See my confessions on page 2 of this thread.

[Kube]

Originally Posted by Ramblin Reck

No we did not bench bleed the m/cyl before installing
We disconnected the rear lines and got some air out of the m/cyl while still installed on car

You do not need to bleed a single reservoir master cylinder.

[jayvee34]

Originally Posted by Kube

You do not need to bleed a single reservoir master cylinder.

Please explain why single reservoir master cylinders do not require bleeding,
while double reservoir master cylinders do. In reality are not double
reservoirs separated into front and rear brakes, which would be the same as
two single reservoirs? Not being negative about this, I just want to learn
if I am wrong about my thinking. Thanks.