Pumping the brakes

[wolfy]

So I got my new windsor and love it.  Opened the master cylinder up to do my regular checks.  The fluid was nice and dark like soda or tea... yuk! 

 

Some background on my brakes.  The pedal is too low for my liking.  On my 52 GMC, I had the old Huck style brakes, and I had those adjusted so the pedal was high and tight!  Worked great every time.  On that truck I replaced everything all the brakes,  that was due to need.  All the parts were beyond shot.  One drum was split in half literally and welded back together. 

 

So on my windsor I want to get the pedal high and tight again.  I have a factory service manual, and my pedal is too low!  The free play is within spec.  I still need to check "B" play.  But I was just wanting some guidance from you experts. 

 

Here is my scenario.  You can pump the brakes and the pedal gets nice and high, but you have to do this every time. The car stops great!  no pulling noises or anything.  The only problem is a "low" pedal. Oh and everything is stock as far as I can tell. 

 

What I have done so far:

1. Bled the brakes.  No air bubbles in there, just the nasty old fluid.  Got the fluid nice and clean and clear.  No air.  Bled the passenger rear then drivers rear, then the front bottom passenger, then top, then the drivers bottom and top. 
2. Pedal felt better, still same problem with the pumping.  But when the brakes engage, the feel is better.  New fluid much better!
3. So I checked the adjustments, minor adjustments only.  All were what I would say is right on.  Very close to dragging.  I was disappointed this was the case.  I was hoping something was off, not the case.
4. I don't have any leaks that I can tell.  I still have NOT pulled the wheels and drums yet. 

What are your thoughts as to check next.  My gut tells me that my master cylinder needs to be replaced.  Anything else you guys can think of?  I will check to see what or how much fluid comes out of the relief port on the MC.  Just curious what you guys think.  Sorry I am new to these cars.  But I am learning. 

 

If I need a MC I found this site out.  http://www.oldmoparts.com/parts-service-brakes.aspx

Looks like I need the G-152 correct? 

 

PS just a dumb quick question.  My car is a C48 correct:)  Also it has the 251 flat head 6 correct?  Any nick names or slang terms for that, so I can at least sound like I know something...

 

Edited June 10, 2015 by wolfy

[Don Coatney]

If you must pump the pedal every time to get good "pressure" then you have air in the system and need to do more bleeding. This is assuming that there are no leaks in the system. Does your manual mention use of the Ammco or Miller tool to correctly adjust your Lockheed brakes?

[P15-D24]

Or you have a leak in the brake line.  

As Don noted diagnosis is simple: pumping mean air in line, find out why.

Low pedal mean shoes out of adjustment, find out why (major/minor adjustment, lining worn out)

[jeffsunzeri]

Don's right, if you get an elevated pedal by pumping, there is air being introduced.

Two immediate suspects come to mind:

1. Master cylinder is worn, and should be replaced.

2. On the MoPar double-leading-shoe front brake, the cylinders can harbor a small air bubble due to the position of the wheel cylinder despite repeated bleeding. Two easier things can help remove that last little bubble; pressure bleeding and vacuum bleeding.

On my own front brakes I have removed the front cylinders and bench bled them to make sure no bubbles exist, capped them off and re-installed wet to an already bled line. That seems to get rid of 100% of any micro-bubbles hiding out.

On your car, I think I'd attack the master cylinder first.

In order to bring the pedal up as high as possible, you may be confronted with installing new drums or fitting shoes with extra thickness. Use a good drum caliper to measure your drums against factory specs. I've had to deal with that on several old MoPars. Good spec drums are getting scarce for some vehicles, but some are being reproduced, so you may be in luck.

As for the 251, I call it the "long block" flathead six, as opposed to the 202,218,230 "short block". The "long block" is about 25" long while the other is about 23".

Edited June 10, 2015 by jeffsunzeri

[desoto1939]

You should pull the brake drums to checkthe condition of the brake shoes and to see if you have any leakage at the wheel cylinders. Could also be that you might need to replace the shoes because they migh be past their serviceable wear limit or they could also be out of adjustment.

 

The use of the AMMCO brake gage tool of the miller factory brake tool will help you determine if the need adjustment.  I do find that out of adjustment brakes shoes seem to cause a soft pedal.

 

Rich Hartung

Desoto1939@aol.com

[Jerry Roberts]

Also look for seepage from the master cylinder . 

[wolfy]

If you must pump the pedal every time to get good "pressure" then you have air in the system and need to do more bleeding. This is assuming that there are no leaks in the system. Does your manual mention use of the Ammco or Miller tool to correctly adjust your Lockheed brakes?

 

Don, thank you so much.  My manual does mention a special tool to do the major brake adjustment.  See I thought that there is air in the system as well.  But I did bleed them quite a bit but that was NOT with any vacuum bleeders.  All done manually.  I am going to the buy a bleeding tool soon to see if that helps.  I bled out all that old fluid and not a bit of air was there.  Bled out a full quart of fluid. 

 

Or you have a leak in the brake line.  

As Don noted diagnosis is simple: pumping mean air in line, find out why.

Low pedal mean shoes out of adjustment, find out why (major/minor adjustment, lining worn out)

 

That is what I was hoping for, just that the shoes needed adjusted.  The minor adjustment is spot on.  I turn the adjuster just a very very bit and the brakes engage.  However I have NOT checked the Major adjustments yet.  Maybe that is the issue?  The car stops great, doesn't pull and does stop very very good. 

 

Don's right, if you get an elevated pedal by pumping, there is air being introduced.

Two immediate suspects come to mind:

1. Master cylinder is worn, and should be replaced.

2. On the MoPar double-leading-shoe front brake, the cylinders can harbor a small air bubble due to the position of the wheel cylinder despite repeated bleeding. Two easier things can help remove that last little bubble; pressure bleeding and vacuum bleeding.

On my own front brakes I have removed the front cylinders and bench bled them to make sure no bubbles exist, capped them off and re-installed wet to an already bled line. That seems to get rid of 100% of any micro-bubbles hiding out.

On your car, I think I'd attack the master cylinder first.

In order to bring the pedal up as high as possible, you may be confronted with installing new drums or fitting shoes with extra thickness. Use a good drum caliper to measure your drums against factory specs. I've had to deal with that on several old MoPars. Good spec drums are getting scarce for some vehicles, but some are being reproduced, so you may be in luck.

As for the 251, I call it the "long block" flathead six, as opposed to the 202,218,230 "short block". The "long block" is about 25" long while the other is about 23".

Thank you so much for the help!  My gut tells me its the MC, but that is without pulling the drums yet.  I hope to get to it this weekend.  But from the outside everything looks good.  The MC was dry.  Not it has some fluid down it because I overfilled it.

 

 

You should pull the brake drums to checkthe condition of the brake shoes and to see if you have any leakage at the wheel cylinders. Could also be that you might need to replace the shoes because they migh be past their serviceable wear limit or they could also be out of adjustment.

 

The use of the AMMCO brake gage tool of the miller factory brake tool will help you determine if the need adjustment.  I do find that out of adjustment brakes shoes seem to cause a soft pedal.

 

Rich Hartung

Desoto1939@aol.com

I agree.  I will get to pulling the drums soon.  I do not have any specialty brake gage tools.  I will have to get buy without these unless I can get one fairly cheep. 

 

Also look for seepage from the master cylinder . 

 

Thanks.  My main concern is this.  The MC was dry on the outside.  What I was thinking that the fluid was going past the internal seals or they are worn. I have had a few vehicles in the past that did this but they were 1980 vintage.  Replaced the MC and it was good. 

 

I will post back some results hopefully soon! Hopefully it is just some air, but after the manual bleeding not any change in the "pumping" action.  Now when you get the brakes to grab, the pedal feel is better.   Which I assume is from the fresh fluid. 

 

So if I need to get a MC is this the one?

If I need a MC I found this site out.  http://www.oldmopart...ice-brakes.aspx

Looks like I need the G-152 correct?

[Don Coatney]

Do a goggle search for garden sprayer brake bleeder. You can make one for next to nothing.

[P15-D24]

Do a goggle search for garden sprayer brake bleeder. You can make one for next to nothing.

To Don's point go the pressure bleeder route, not a vacuum bleeder. When everything is correct you should be able to fully bleed the entire system in two trips around the car. 

[ptwothree]

Her is another system check.   Pump up the pedal till it's high then keep a constant pressure on it and see if the pedal wants  to fall away from your foot.  If it does, that would indicate air in the system or fluid leaking out.  If it stays up and doesn't move, too much clearance exist between the drum and the shoes.  Adjustment if you are lucky,  parts replacement if not.

[wolfy]

Okay, thanks again for all the help here guys.  I had about 5 min yesterday to work on the car.  So I looked in the MC and checked the B travel per the manual.  I was looking at the fluid coming back through the relief port.  Everything checked good against the manual.  Nothing looked strange. 

 

So I went and bought this brake bleeder yesterday afternoon. 

http://www.harborfreight.com/brake-fluid-bleeder-92924.html

 

I am not sure what the difference between a pressure bleeder and a vacuum bleeder.  Hopefully this will help.  I am planning on pulling the drums and checking things out this weekend... I hope;)

 

So the results of your test ptwothree is when I pump up the pedal, it stays nice and solid, high and tight.  The thing is I cannot adjust the shoes out anymore, at least for the minor adjustment.  I have went through it twice and they are all so close to the drums if I move them out any farther they will lock up.  Right now there is no drag.  That would be for the 6 total adjusters!  Maybe some Major adjustments are needed?

[TodFitch]

. . . So I went and bought this brake bleeder yesterday afternoon. 

http://www.harborfreight.com/brake-fluid-bleeder-92924.html

 

I am not sure what the difference between a pressure bleeder and a vacuum bleeder.  Hopefully this will help. . .

That is a vacuum bleeder, just using the flow of air from your air compressor to create a vacuum via Venturi effect. And at $29 (non-sale) it does not seem like a very good deal to me.

 

I made up a pressure bleeder from a garden sprayer and some fittings for less than that but your cost may vary as part of it is coming up with a pressure tight way to attach it to your master cylinder and my '33/34 master cylinder is different from the later ones.

[mopar_earl]

Her is another system check. Pump up the pedal till it's high then keep a constant pressure on it and see if the pedal wants to fall away from your foot. If it does, that would indicate air in the system or fluid leaking out. If it stays up and doesn't move, too much clearance exist between the drum and the shoes. Adjustment if you are lucky, parts replacement if not.

I agree. Out of adjustment drum brakes will get a better pedal when pumped. Disc brakes will do this when the piston is all the way till you pump it out than you get a firm high pedal. On drum brakes the wheel cylinder pistons travel more each time you pump fluid to them until the shoes contact the drum. The bigger the space between the drum and shoes will result in more pumps needed to get a higher pedal. Pretty common on drum brakes when the self adjusts stop working.

Earl

[wolfy]

I completely agree.  What is strange is I have the brake adjustments out as far as they can go before they hit the drums.  I will pull the drums this weekend to see what the condition of the brake shoes are.  But for the minor adjustments they are as close as I can get them before they hit the drums. 

 

 

So a pressurized bleeder must pressurize the MC to bleed the brakes?  Like this one? http://www.homedepot.com/p/GearWrench-4-Qt-Brake-Bleeder-Tank-with-10-1-2-in-Hose-2901D/204622152

 

Sorry I am new to bleeders, but not to brakes.  I have done brakes on several vehicles.  The only bleeders I have seen are the pump type similar to the one I got.  Both create a vacuum effect, thus sucking the fluid out of the bleeder valve.

[TodFitch]

. . . Like this one? http://www.homedepot.com/p/GearWrench-4-Qt-Brake-Bleeder-Tank-with-10-1-2-in-Hose-2901D/204622152

 

I guess one could buy one like that.

 

I started with one of these http://www.osh.com/Osh-Categories/Outdoor/Lawn-%26-Garden/Garden-Tools/Spreaders%2C-Sprayers-and-Parts/H-D-Hudson-Poly-Handy%3F-Sprayer%2C-0-5-gal/p/6783880and added a Schrader valve to the top side and then cut off the spray wand and created an adaptor for my master cylinder cap. My total cost was about 1/4 to 1/3 what the one you linked to costs.

 

The reason for the Schrader (tire) valve was two fold:

1.I use DOT5 and did not want to have the built in pump bubbling air through the fluid as it would take forever for the air to come out. I don't think DOT3 would be as bad on that.

2. I can use my tire filling setup with its built in pressure gauge to fill the sprayer/bleeder and know what pressure I've got. In my setup it seems that 15 or so PSI is enough pressure to bleed the brakes.

[desoto1939]

I completely agree.  What is strange is I have the brake adjustments out as far as they can go before they hit the drums.  I will pull the drums this weekend to see what the condition of the brake shoes are.  But for the minor adjustments they are as close as I can get them before they hit the drums. 

 

 

So a pressurized bleeder must pressurize the MC to bleed the brakes?  Like this one? http://www.homedepot.com/p/GearWrench-4-Qt-Brake-Bleeder-Tank-with-10-1-2-in-Hose-2901D/204622152

 

Sorry I am new to bleeders, but not to brakes.  I have done brakes on several vehicles.  The only bleeders I have seen are the pump type similar to the one I got.  Both create a vacuum effect, thus sucking the fluid out of the bleeder valve.

So are you saying that you have  used the upper adjusting bolt and you have gone out as far as you can and you do not lock the drum when doing  this on one of the shoes?  If this is happening then the shoes might have worn down and they might need to be replaced or there might be a possibility that the drums have been overcut past the maximum. You should have the drums micrometered to see what they are.  If they have been over cut then you might be able to use a riveted lining and put shims under the lining to make up the difference or get nos drums.

 

So I really think the next step ist o pull the drums to see what is going on with each wheel.

 

Rich HArtung

Desoto1939@aol.com

[wolfy]

So are you saying that you have  used the upper adjusting bolt and you have gone out as far as you can and you do not lock the drum when doing  this on one of the shoes?  If this is happening then the shoes might have worn down and they might need to be replaced or there might be a possibility that the drums have been overcut past the maximum. You should have the drums micrometered to see what they are.  If they have been over cut then you might be able to use a riveted lining and put shims under the lining to make up the difference or get nos drums.

 

So I really think the next step ist o pull the drums to see what is going on with each wheel.

 

Rich HArtung

Desoto1939@aol.com

Yes the bolt that I adjusted was for the minor adjustment.  I moved the shoes out as far as i can before the the shoes hit the drums and stop the wheel from turning.  

 

All that you have mentioned is possible as I haven't inspected the drums or shoes yet.  I completely agree the next step should be to pull the drums! I wonder if my local parts place can measure them for me, as I don't have the tools to measure them. 

 

Thanks for the help.  Oh one nice thing is I got the car titled and transfered to me now officially!  Got my 1950 vintage KS license plate as well.  It's nice that the state of KS lets me use that instead of the antique tag.  Looks cool!

[wolfy]

Tod, yeah I don't want to spend that much on a brake bleeder.  I got that harbor freight one for about half that price after the coupons...  If anything this will save my poor wife in the future from operating the pedal all the time.  She has been so great to help me out.

[wolfy]

Okay I pulled all the drums off. The rears were harder and needed a puller.  Anyway all brakes were in very good shape!  Shoes, wheel cylinders, springs, etc, all look new.  The shoes all look like they have worn evenly as well. I can't see anything what I would call strange.  Except on the lower cylinder push rod on the front looks out of alignment to me. 

 

Please see the pics below and evaluate.  But no leaks or anything bad like that. 

 

So I don't have that nice fancy tool that my shop manual says I need.  I am assuming they want you to use this to make sure the shoes are on the same radius as the drums.  As well as angle.  So I used a string to check the radius of the shoes.  They were all dead on! Within less then 1mm.  Maybe not the correct thinking here, but I think I have shown that the adjustments are on.  Please let me know.

 

[wolfy]

[wolfy]

[wolfy]

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[TodFitch]

Brake lining to drum clearance specifications vary by year but I think the P15 era and a little later were 0.006" which, if I run my calculator correctly, is about 0.15mm. Not sure you can accurately measure that closely with your string and a little bit too much clearance on the major adjustors does make a big difference in the braking effectiveness.

[wolfy]

Brake lining to drum clearance specifications vary by year but I think the P15 era and a little later were 0.006" which, if I run my calculator correctly, is about 0.15mm. Not sure you can accurately measure that closely with your string and a little bit too much clearance on the major adjustors does make a big difference in the braking effectiveness.

Thanks Tod.  Yes I agree with you.  To say that the sting method was to that point of accuracy would be wrong;)  I am a mechanical engineer by trade and I would not say that method is accurate to that standard. 

 

There is no change in my pedal at all.  But shouldn't be as I didn't change anything.  So my pedal when I pump it is about 2.0" difference in the pedal height.  Meaning if I just hit the brakes the pedal is about 2" lower then if I pump the pedal say 2 times.  The pedal will then be 2" higher then normal. 

 

So what do you guys think is my next steps. Would .15mm translate to 2" of brake pedal travel?  Or do you think I still possibly have air in my system?  Remember I did bleed the brakes manually with my sweet wife helping me.  I could NOT see any bubbles.  I did bleed the front lower cylinder first.

 

Is my master cylinder shot or going out?  Or is this something that I will have to "live" with...  Thanks so much for the help guys

[desoto1939]

wolfy:  This is rich Hartung. I looked at the pictures and I can tellthat someone has  turned the eccentric at some point in its life time.  I sent you a PM about the Ammco brake tool.

 

Rich Hartung

desoto1939@aol.com