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Brake dodge WC51/52

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Hello to all,

probertly it is allready asked but i will ask again.

I have renewed the brake rubbers on all my brake cylinders, cleand and re-don the inside with the grinding tool. The main brake cylinder got an overhaul and i replaced the fauly flex lines. System purged all ok. Before entering the brake fluid i have adjusted all the brakes as per the manual.

Now it comes, i drove about 20 km and got verry hot brakes. I have re adjusted the brakes again but after 20 KM the same problem. I suspect the master brake cylinder not comming back, it is strange that all 4 brakes are hot and blocking but not enough to have the dodge not moving at all. The free pedal space is around 1.5 inch.

Does some one have an idea what i can do? I will disconnect the brake line from the master to see if there is pressure left in the system.

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Posted (edited)

1.5 inch is Not enough free travel on the brake pedal, do not go by the original workshop manuals measurment, adjust the master cylinder pushrod to give a Lot More free play, start with At Least 3 to 4 inches of free pedal movement, then road test, it may need more adjustment, that will cure the problem of brakes binding, its a common problem with Dodge brakes of not enough free play on the master cylinder pushrod causing the brakes to bind, get hot, the fluid expands and brakes lock on

Edited by Nick Johns

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1.5 inch is Not enough free travel on the brake pedal, do not go by the original workshop manuals measurment, adjust the master cylinder pushrod to give a Lot More free play, start with At Least 3 to 4 inches of free pedal movement, then road test, it may need more adjustment, that will cure the problem of brakes binding, its a common problem with Dodge brakes of not enough free play on the master cylinder pushrod causing the brakes to bind, get hot, the fluid expands and brakes lock on

 

Hello Nick,

 

thanks for your answer. Will give it more play. If this is working than i will re adjust all brake cyl. I made a quick adjustment when i tried for the second time just to get home.

 

Bram

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If you have enough free play in the brake pedal and pushrod, then your brake linings are too close to the drum somewhere, and when it heats up it is back-pressurising the system against the output check valve.

 

Re-adjust all eight linings to give them more clearance, then re-test.

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There should also be a gap between the fluid and top of the master cylinder. The manual says 1 1/2 press of the pedal.

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There should also be a gap between the fluid and top of the master cylinder. The manual says 1 1/2 press of the pedal.

 

Please explane this.

My system was working before i changed the cylinder piston rubbers and master cyl. due to leakage. As it is a former french army dodge they have installed an extra reservoir connected to the fill plug hole on the master cyl.. this works fine. I have given the brake pedal around 3,5 inch free play before it hits the master plunger. I have checked the rotation of the wheel, that is free now. Only have little oval drums but thats no problem. I had the feeling that the master brake piston is not moving quickly back, could be a small air left over in the system. No time yet to drive and check what its doing when working

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Hi Gordon,

you're talking about a valve? Where is that located? For me it is an easy and simple system. You have the master plunjer, pushed by the pedal pressing the brake cylinders. Return when no pressure is by the brake shoe spring, until it is stopped by the adjustment bolt and the little spring in the master cyl. I had a problem with purging the back wheels, the fluid came not trough and the front brakes stayed pressurised. After i had changed the flex hose, completely worn out, i could purge the system normaly

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Posted (edited)

Some master cylinders have a non-return check valve to stop the fluid getting back into the cylinder quickly. It allows the piston bore to draw fluid down from the reservoir rather than pull it back out the brake lines when the piston returns. I have seen Dodge cylinders with, and without this check. It is usually right at the cylinder output, just before the brake light switch position.

 

If the system heats up, it can pressurise the whole system against this check, but this is only an issue if there is one in line. Many of the Master Cylinder rebuild kits I have seen come with this check valve.

Edited by Gordon_M

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The diagram attached may be useful to you.

Check both the ports highlighted are clear and that the lip of pressure cup clears the vent port when the brake pedal is in the off position. You can do this with a 0.6mm piece of welding wire bent at two 90' angles so that it will go into the reservoir and into the ports.

If the vent port is blocked or obstructed several applications of the pedal will build residual pressure in the lines.

 

Pete

 

Master cylinder.jpg

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Hello Pete,

thanks for the advice. I just did a testrun and same hasle. Yesterday adjusted the brake clearence as adviced into 3.5 inch. Checked the left front wheel and it turns freely even after braking. After todays testrun i have the feeling that the piston is not returning completely into the rest possition and by this keeping the lines pressurised. What i will do now is adjust all brakes so the wheels will turn freely and see if i can open those vent holes.

But give me some time i'm verry bussy at this moment

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Hello to all,

finaly found time to check the brake system again. I have removed the master brake cyl. checked the wholes, as mention before. When i did the revision there was also a rubber ring delivered to be put at the end, where the push rod is comming true. Since all the openings where free i had the feeling that the piston could not return completely to the rest possition and due to that one of the openings where half blocked. I have taken out that rubber ring re-installed the brake cyl. Adjusted all the clearens on the brake shoes. For now it looks good, still some air in the system but that will be gone when i have more brake fluid. Was running out of it. When i brake now and release the brakes the wheels are turning straight away freely.

Hopefully it will be fine now. Thanks to all for helping out with ideas and suggestions.

Bram

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Looks like you have got the problem sorted :yay:

 

thanks for coming back and letting us know the outcome it's useful to for all of us on HMVF as it helps to track down problems and remedies that we may encounter. :tup::

 

Pete

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When the work they work well. When they don't AHHHHH!:D

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They only thing i wonder is that if the piston is comming back to the rest postion whitout the rubber seal it might be damaged after i while. Maybe i will cut of a small part of the rubber and install it.

 

Of course it is normal to give a feed back. We all need info to attack the issues comming with these old vehicles.:D

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Well i have tried to bleed the system but somewhere air stays in. Does someone have a good procedure to get it out? When i open de airnipples only fluid is comming out no bubbles. But when braking is spongie. But the good news is that if it brakes its better than before.

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I have bled Hyd systems From the bleeder before but it is time consuming. You have to make sure that the brake pedal/cylinder is right back. Then start furthest from the reservoir push enough through to pass the T coupling, then go to the other side of the axle push it through to the reservoir. Then do the next closest axle. You must be able to catch the excess coming from the filler. It is usually better to bottom fill radiators the coolant pushes the air out as the system slowly fills.

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Well i have tried to bleed the system but somewhere air stays in. Does someone have a good procedure to get it out? When i open de airnipples only fluid is comming out no bubbles. But when braking is spongie. But the good news is that if it brakes its better than before.

 

Now stage two :cool2: Each of the wheels has an inspection plate on the brake drum and four adjusters. Get your feller gauges out and adjust each wheel. THEN click the top adjusters till the wheel stops and back of one notch. Results in brakes that will put you through the windscreen.

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Hi Tony,

 

thats what i did the first time before bleeding the system. I will do it again but it is not so easy to have it done due to the fact that the drums are a little bit oval so when you have adjusted the brakeshoe to the correct level it will hit somewhere the drum. anyway i will start over again with the process and give some slack when its hitting. Front is braking verry well, the dodge is diving so i will start on the back and see what its doing.

 

Brdgs

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Hi Tony,

 

but it is not so easy to have it done due to the fact that the drums are a little bit oval so when you have adjusted the brakeshoe to the correct level it will hit somewhere the drum.

Brdgs

 

That may well be the root of your adjustment problem, with out of true drums it is not possible to adjust to obtain 100% of available shoe contact and as a result your braking efficiency will be compromised, you may need to think about getting them skimmed.

 

Pete

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That may well be the root of your adjustment problem, with out of true drums it is not possible to adjust to obtain 100% of available shoe contact and as a result your braking efficiency will be compromised, you may need to think about getting them skimmed.

 

 

and then if the drums are skimmed the brake shoes will need thicker linings to fit the new drum radius, (re-profiling shoes of this size may not be possible as it would make the linings too thin at the ends).

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If you have had the drums off, it may just be that the faces have got something in between and are not sitting flush.

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Thanks for the feed back, all of you. I will see and check everything again and give the feedback later. Quite bussy at this moment but need to have it fixed before the weekend of the 9-10 Sept. keep you posted.

 

Bram

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If it's any help (Haa!) took me four seperate adjustments of the wheels before the brakes worked properly. May be worth setting the bottom adjusters by feeler gauge then the top ones by spin and stop method.

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Posted (edited)
Thanks for the feed back, all of you. I will see and check everything again and give the feedback later. Quite bussy at this moment but need to have it fixed before the weekend of the 9-10 Sept. keep you posted.

 

Bram

I was talking to Amanda on the Jeeparts stand at war & peace show and apparently their stock of Dodge master cylinders were all found to be faulty, they have just had to return a batch of the new faulty ones to their supplier in France, so that may be your problem

Edited by Nick Johns

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