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Pumping the brakes


wolfy
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The shoes look like they have completely and properly worn in to match and make 100% contact with the drum caused by the previous owner's driving.

You have adjusted the 3/4" hex bolt minor "TOE" adjustments on all 4 wheels by turning (8) the adjuster bolts outwards and down till the drum locks and then back off (up) just till each drum turns freely? I would not tamper with a major adjustment as the shoes are seated and worn in.

If this is the case and the brakes have no air in the system after proper complete bleeding I'd double check pedal free play--1/2" and make sure the M/cyl piston completely returns after each pedal stroke...look down into the M/cyl to see the two ports ( bigger port and smaller Relief port) are not blocked by the silver aluminum piston.

If the above are all ok I'd look at the Master cylinder for the problem.

Some factory info on the M/cylinder...

PS..I did see a wetness on the spring below one of your front wheel cylinders-on the spring! See pic.

Bob

post-302-0-39533000-1434247367_thumb.jpg

post-302-0-91842700-1434247475_thumb.jpg

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If you have to pump the brakes to get the pedal up and firm you have air in the system. Either you didn't get it all out while bleeding or you have a leak (most likely) Your are wasting your time messing with shoe adjustments until your hydraulic system has integrity. Second when you get the hydraulic issue resolved the most important piece for adjusting the shoes it to verify your drums are turned and trued up. If the drums are out of round you will never get good brake adjustment or performance. Remember your talking about 0.006 clearance and if the drum is out of round even half of that you won't to able to correctly adjust the shoes for best performance. 

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You might want to check Rock Auto or eBay  for the MC or fuel pump and save some money.  Rock  Auto  MC =$70 to $150,  FP = $60.

 

 Question for the peanut gallery : I have a 49 Windsor and I just did the back brakes. Looking at the pictures here , I notice my car doesn't have the springs and clips at the top of each shoes. Is this a necessity for proper function? I see them for sale on EBay all the time. Also, what is the function of the electronics on the air cleaner support rod? Mine doesn't have that but I've seen pictures of 49"s that do.

 

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You might want to check Rock Auto or eBay  for the MC or fuel pump and save some money.  Rock  Auto  MC =$70 to $150,  FP = $60.

 

 Question for the peanut gallery : I have a 49 Windsor and I just did the back brakes. Looking at the pictures here , I notice my car doesn't have the springs and clips at the top of each shoes. Is this a necessity for proper function? I see them for sale on EBay all the time. Also, what is the function of the electronics on the air cleaner support rod? Mine doesn't have that but I've seen pictures of 49"s that do.

so are you asking about the return spring and the small metal cap and rod that goes through each shoe into the backing plate?  If you have dula wheel cylinders then you will need the two long springs thes are used to pull the brake show back from the drum after releasing the brake pedal.  The other small metal cap is used to hold the shoe against the backing plate, you should have the spring and the small cap and rod and a small spring.

 

The other question, is do you have a fluid drive on your car? The connection is part of the relay for the fluid drive setup.

 

Rich Hartung

Desoto1939@aol.com

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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

Rich, I just saw your email.  thank you so much! I will consider your offer.  I may try to talk to an old mechanic that is close to me.  He is a great guy and would tell me either way if he could do this work and not charge me for that part;)  I may go talk to him about this as well. 

 

The shoes look like they have completely and properly worn in to match and make 100% contact with the drum caused by the previous owner's driving.

You have adjusted the 3/4" hex bolt minor "TOE" adjustments on all 4 wheels by turning (8) the adjuster bolts outwards and down till the drum locks and then back off (up) just till each drum turns freely? I would not tamper with a major adjustment as the shoes are seated and worn in.

If this is the case and the brakes have no air in the system after proper complete bleeding I'd double check pedal free play--1/2" and make sure the M/cyl piston completely returns after each pedal stroke...look down into the M/cyl to see the two ports ( bigger port and smaller Relief port) are not blocked by the silver aluminum piston.

If the above are all ok I'd look at the Master cylinder for the problem.

Some factory info on the M/cylinder...

PS..I did see a wetness on the spring below one of your front wheel cylinders-on the spring! See pic.

Bob

Bob, thank you.  This is what I thought when I took off the drums.  I made sure to look at the shoes before I cleaned them off.  The wear on them looked nice and even. 

Yes that minor adjustments on all 4 wheels is the only bolt I have touched.  Yes I did both adjustments per wheel, 8 total.  I cannot get them any closer without touching the drums.  I have gone through this 3 times now.

 

So as their being air in the system, I don't think so.  I have bled the brakes no air came out, no change in the pumping action.  I ran almost a quart through.  Yesterday I also tried my compressed air venturi type bleeder.  No change.  To 100% rule out there is no air, I can't, but it is beyond me to get that air out. 

 

I just went and looked at the MC again.  I cannot see the piston until I press on the pedal.  One thing I did notice was that I cannot see the level of the fluid going down when I pump the pedal.  The pedal is higher but the level stays the same.  That or it lowered so little I could not see it.  This makes me think that the shoes are adjusted properly.  This also makes me think that there is no air in the system.  If there were air I would suspect that the fluid level would go down so the fluid could "compress" the air.  What are your thoughts on this?  These are just my speculations.  Obviously I am no expert here!!!

 

Oh I saw that wetness as well.  Here is the pic before I cleaned the parts.  I believe what you are seeing is just some left over brake cleaner drying.  I did take the pic right after I cleaned them.  The before pic doesn't show any sign of wetness.

IMG_0481_zpsigoijlmg.jpg

 

If you have to pump the brakes to get the pedal up and firm you have air in the system. Either you didn't get it all out while bleeding or you have a leak (most likely) Your are wasting your time messing with shoe adjustments until your hydraulic system has integrity. Second when you get the hydraulic issue resolved the most important piece for adjusting the shoes it to verify your drums are turned and trued up. If the drums are out of round you will never get good brake adjustment or performance. Remember your talking about 0.006 clearance and if the drum is out of round even half of that you won't to able to correctly adjust the shoes for best performance. 

This is still a possibility!  Just to give you a frame of reference I am able to pump my pedal up 2" or more!  Would .0006" x 8 shoes make this difference?  I'm just trying to get a feeling if you guys think that could make up that much pedal travel.  As I have no idea:)

 

I just want to thank you all again for your help with this!  You all have been great.

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I have learned over the years of doing  already completely worn in lockheed brakes and linings that as long as there is a very slight drag on the drums after a minor maintenence adjustment the pedal will imediately be high and good to go.

 

Even backing off just a little bit more so as no drag pedal will still be high and rock hard.

 

The ammco tool is handy to use on a new complete brake job to set the shoes but they should be arced to each drum for accurate fast shoe positioning. It is not necessary on completely worn in linings IMO.

 

If it takes two pumps to get the pedal high but the pedal still seems rubbery there is still possibly air in the system. Another cause is the shoes are not fitting the drums 100% because of the incorrect shoe arc to drum fit.. does not seem to be the case here.

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. Also, what is the function of the electronics on the air cleaner support rod? Mine doesn't have that but I've seen pictures of 49"s that do.

 

 

The relay on the air cleaner support is for vehicles that have the semi-automatic transmission such as the M5, or M6 rather than just having a regular 3 speed behind the fluid drive coupling.

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I have learned over the years of doing  already completely worn in lockheed brakes and linings that as long as there is a very slight drag on the drums after a minor maintenence adjustment the pedal will imediately be high and good to go.

 

Even backing off just a little bit more so as no drag pedal will still be high and rock hard.

 

The ammco tool is handy to use on a new complete brake job to set the shoes but they should be arced to each drum for accurate fast shoe positioning. It is not necessary on completely worn in linings IMO.

 

If it takes two pumps to get the pedal high but the pedal still seems rubbery there is still possibly air in the system. Another cause is the shoes are not fitting the drums 100% because of the incorrect shoe arc to drum fit.. does not seem to be the case here.

 

Thanks!  Yes that has been my experience with my "huck" brakes on my 52 GMC.  That is why I am struggling here trying to learn about these different brakes.  On my 52 I had to replace everything as it was all not worth saving. 

 

It takes two pumps to get the pedal high, but the pedal is nice and firm after this.  Heck even when I go to stop without pumping the pedal is firm, just lower. 

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is there any possibility that you drums have been overcut.  Have them measured with a good brake drum micrometer.  Any good quality shop that does brakes should have the tool. So you brakes should be 11 inches if not cut.  Go see what they currently are measuring.  This also might be your problem, but have to start to eliminate so this is the first spot to check since you already hav ethe drums off the car.  Let us know what the measurements are so we might be able to help you.

 

Rich Hartung

Desoto1939@aol.com

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If you can crank all the adjusters up until the shoes drag, the pedal should be hard and high, if its own linkage is adjusted right.

 

If it feels soft at the top or you can pump the brakes and make the pedal come higher, there is air and moisture in the system. Get it out.

 

Usually I can just crack the lines at the wheel cyls, then the bleeders, one by one, and pump the pedal each time to relieve any major air. Then I back bleed the system by manually compressing the shoes. Of course the drums must come off one at a time to do this, so it should be done while replacing shoes.

 

Before back-bleeding, it's good to flush out all the old fluid as well as possible. Otherwise you push dirty fluid into the master cylinder.

 

Air always gets trapped in the highest spots in the system.  The manual says to work on a level ground, but it sometimes helps to jack the car up crooked, or park one wheel up on a block, to help the air get past a high spot. The top of the rear flex hose is often near the highest point of the line in a master-under-floor car. I often find air trapped there.

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I went and purchased the caliper so I should be able to measure the drums now. The drums could be over cut. But wouldn't the pedal be high and tight since I have the minor adjusters so close to the drums already?

The adjusters are so close I cannot get them any closer without locking up the brakes. I have also replaced all the fluid and bled brakes three times. Once was with a vacuum assisted brake bleeder. Not saying there isn't any air in there but I cannot find any air bubbles or i can't get them out.

My pedal is not spongy. It is just too low. I can pump it to get it higher. But when it's low or high it is tight.

Edited by wolfy
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You don't have air, you have an adjustment problem. 

 

Bring it down to Columbia, Mo and we'll fix it. You're not that far away. Or borrow my Miller tool (what the dealer used) and set it yourself. It's more labor intensive than the ammco tool, but works just as well.

 

Gene 

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You don't have air, you have an adjustment problem. 

 

Bring it down to Columbia, Mo and we'll fix it. You're not that far away. Or borrow my Miller tool (what the dealer used) and set it yourself. It's more labor intensive than the ammco tool, but works just as well.

 

Gene 

Disagree 100%. If the pedal is high and firm after pumping adjustment is correct. Have to pump indicates air in the lines. When you did the bleeding did you follow the correct sequence? Start at the wheel cylinder farthest from the master, finishing with the one closest to the master.  

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Disagree 100%. If the pedal is high and firm after pumping adjustment is correct. Have to pump indicates air in the lines. When you did the bleeding did you follow the correct sequence? Start at the wheel cylinder farthest from the master, finishing with the one closest to the master.  

 

This was from post #1:

 

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.
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There is something going on with those push rods from the cylinder to the shoe that are at a severe angle. Some are aligned straight, there is at least one that is at a severe angle. That is not right. Not sure it has anything to do with the low peddler, but it's not right.

I'll be going back through KC around 6-7 July and would be happy to drop off the adjustment tools for you to use if you'd like.

Edited by austinsailor
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Some people still think the world is flat, doesn't make it so.

Offer still stands, I'll be in Columbia about 2 weeks.

PM me if you're interested.

I'm with you. I put my money on adjustment/travel issue. Pumping the brakes takes up this adjustment/travel issue.

Very generous of you to loan out a tool! A true mopar got your back guy!!

Earl

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I'm with you. I put my money on adjustment/travel issue. Pumping the brakes takes up this adjustment/travel issue. . . 

 

I actually think it's mechanical too, and not air because the pedal is hard. Air means soft/spongy. Moisture means soft/spongy only when very hot (steam vs. just cold air)

 

I saw the crooked push rod, but just thought the shoe had dropped from gravity, cocking the rod, & the cylinder appears to be on straight.

 

I'm now thinking that the drums are quite out of true & with lots of taper and the shoes will drag an edge with just slight pressure, but can't seat up square under normal adjustment, requiring extra pumps to take up that motion.

 

Just one more thought though, have the rear wheel bearings been checked for vertical play?

 

If the axle sits high in the housing, the first pump on the brake is taken up as the axle/drum center up on the brake assembly.

Edited by Ulu
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  • 2 weeks later...

Okay, I haven't had to much time to mess with this, but I did pull the drum off in the front again. Just to clarify some items. 

 

My shoes are wearing perfectly evenly.  I don't think my drums are out of round or out of true, because my shoes are wearing nicely.  There is no strange taper.  Also There is ZERO pulsation in the brake pedal. 

 

I hope to meet with Austin soon.  He is kind enough to help me out. 

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Looks like you have confirmed you don't have an adjustment issue. Time to figure out what is going on with the hydraulics Also agree you need to figure out what is going on with the wheel cylinder push rod. 

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Replace the master cylinder no matter what.   When bleeding the brakes there is a proper sequence to get the air out of the front cylinders.  I think its the bottom ones first but not certain.

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I'm dropping the adjustment tool off, probably Friday. I think there is more mechanical going on than just the adjustment myself. Wish I had time to stop and spend an afternoon working on it with him, but I just can't.

I'm real puzzled about the angled rods. Has anyone seen that before? Ever figure it out? I think that is part, but don't understand what is out of whack.

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Sorry no update lately fellas. Austin is dropping off that tool tomorrow! So cool of him.

So I marked those bolts with the arrows and tried turning them to see if that angle of the rod would change. It did not.

I didn't have much time to look any further.

I will verify with the right tools. I'm sure I'll have questions when I get to using that.

I followed the bleeding order from the manual on what one to bleed first. So that shouldn't be the problem.

Just to remind you all. My pedal is firm whether it is low or high. More firm when higher. And the more I pump them the higher it gets.

I think it's either the master cylinder as it is not new like the rest of the brake parts. Or it's the adjustment issue. Remember my minor adjusters are as close as they can be. But the shoe wear looks even. On all the parts.

Thanks everyone! I know we will get this:). With your help for sure;)

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