M151A2 Brakes locking

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Eddie Holland
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M151A2 Brakes locking

Unread post by Eddie Holland » July 25th, 2018, 9:30 am

Ok I recently got my A2 back on the road after sitting idle for 2 years. I have a front left wheel locking up coming home from the 4th of July parade. The wheel was getting very hot. I pulled the drum off last night. I had a hard time getting the drum off. Almost like the brake was on. When I push the pedal I can see only the front pad is moving. So it appears the one piston is locked up. Also the front one was very slow to return when releasing the pedal. Is there a civilian part number for the front brake cylinders? Maybe I can possibly rebuild the cylinders with parts from NAPA? The pads where maybe 3/8 to almost 1/2 thick. Maybe I need new springs also?
Thanks Eddie.

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Re: M151A2 Brakes locking

Unread post by Surveyor » July 25th, 2018, 10:00 am

NAPA Numbers from previous thread...

NAPA part Numbers are:

3/4" wheel cylinder: UP 16535
3/4" wheel cylinder rebuild kit : UP 127
1" wheel cylinder: UP 16534
1" wheel cylinder rebuild kit: UP 106


A2 should have the 1" ones in the front.

I've purchased the 3/4" and spring kits from Orielly's in the past...
BrakeBest Hardware Spring Kit Part # H7037 - Around $9 (does not include adjuster)
BrakeBest 3/4" Wheel Cylinder Part # WC16535 - Around $27

For comaprison prices on ebay.... https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

Shoes - Brake Shoes for 1964 AMC American Oriley's p/n #433

Always good to check the wiki!
1960 M151 Run #1
"There is one nut on a M151 that is very difficult to remove....." - K8icu
"She ain't a Cadillac and she ain't a Rolls, But there ain't nothin' wrong with the radio" - Aaron Tippin
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rickf
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Re: M151A2 Brakes locking

Unread post by rickf » July 25th, 2018, 10:44 am

Front line sells the entire brake kit with all the hardware for a decent price. That way you know you are getting what you need and not bits and pieces from 4 different cars. I figure if the prices are the same it is always better to go with NOS stuff.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Eddie Holland
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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 25th, 2018, 11:49 am

ok thanks everyone!

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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 25th, 2018, 11:53 am

ps I checked the wiki but unless I over looked it all I found was info on the 3/4"

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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 25th, 2018, 9:30 pm

Do i have to take the hub off to get the wheel cylinder off? Also how do I remove the spring that runs from the center of each brake shoe to the backing plate. ? Almost looks like the spring is screwd into the brake shoe? The spring sorta has a rectangle head on the back of the backing plate.
Thanks in advance. PS got the wheel cylinder bleeder screw out the the 2 bolts that hold it on. The fluid that ran out was pretty black. I am guessing from it getting so hot.

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Re: M151A2 Brakes locking

Unread post by Fil Bonica » July 25th, 2018, 9:51 pm

Unloosen the nut enough to slide out the hub enough to get the wheel cylinder clear..
Push a screwdriver in to the retainer spring sufficiently to relieve the tension on the square clip and remove the spring

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Re: M151A2 Brakes locking

Unread post by fowlercal » July 25th, 2018, 11:15 pm

Fil,

UNLOOSEN ?? Is that like to UNTHAW something that is frozen?

Cal

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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 26th, 2018, 10:19 am

since the fluid looks so nasty and I don't know what type is in it, I am wondering the best way to get all the old fluid out. Just take all lines loose on all wheel cylinders and pump the brakes? Is that gonna get it all out? I'm really not a mechanic lol

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Re: M151A2 Brakes locking

Unread post by Fil Bonica » July 26th, 2018, 10:27 am

I talk funny!!

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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 26th, 2018, 11:33 am

Found a good answer from Rickf in and old thread.

"You basically need to disassemble all the wheel cylinders and pump the master cylinder empty and then refill it with the fluid of choice and pump that through the system. That is all the flushing needed. If you are replacing the master cylinder that is even better. If using the old master cylinder you want to try to avoid pushing the pedal all the way to the floor since there can be deposits built up in the bore where the piston does not normally travel. When you force the piston past these deposits sometimes it will damage the seals. Not always but the chance is there."

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Re: M151A2 Brakes locking

Unread post by svramselaar » July 27th, 2018, 2:26 am

hi

to convert to silicone fluid look at below

http://www.jatonkam35s.com/DeuceTechnic ... 0fluid.pdf


george

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rickf
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Re: M151A2 Brakes locking

Unread post by rickf » July 27th, 2018, 9:01 am

George, I have a problem with that procedure, a couple actually. If you read the very beginning it says that civilian vehicles received for military service that need fluid added will be topped off with BSF and the fluid will be retrofitted at the next major brake service. So right away they are mixing the fluids. Then in the actual retrofit procedure it tells how to purge and refill the pressure bleeder but not the vehicle. All it says to do is hook up the pressure bleeder and run the BSF through the system until you see the purple fluid. This is bad because there will be a LOT of mixed fluid especially in the master cylinder and really especially in the wheel cylinders since they fill AND bleed from the top.
As far as I am concerned the master cylinder has to be emptied which can be accomplished just by opening all of the bleeders but you also need to remove the wheel cylinders which is the only way to empty them. When you remove the wheel cylinders the fluid will also drain from the master cylinder and lines from gravity. Once the wheel cylinders are reinstalled and proper bleeding is done you will have all fresh fluid in the system be it DOT 3 or DOT 5.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Eddie Holland
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Re: M151A2 Brakes locking

Unread post by Eddie Holland » July 27th, 2018, 9:31 am

Thank you for the TB. It talks about a pressure filler bleeder? Is that a device I can buy? When I took the left front wheel cylinder off very little fluid dripped out. So I pushed the brake pedal and very dark brown crap came out. The master cylinder was very low so I pour some DOT4 I had in it to flush the line. It finally ran clear. I now need to pull each wheel cylinder and clean or replace. I'm not sure how to get all the fluid out of the lines and which fluid I should go with. :?: Thank you to all for your wisdom.

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Re: M151A2 Brakes locking

Unread post by rickf » July 27th, 2018, 10:24 am

You can buy pressure bleeders BUT, Putting 30. lbs. of pressure in a bleeder will give you a brake fluid milkshake!! No more than 10-15 lbs. less is better to keep from aerating the fluid. Cheap bleeders do not separate the pressurized air from the fluid, you do not want one of them. The better pressure bleeders have a rubber bladder that has air pressure on top and fluid on bottom. Too much pressure will still cause aeration. You really do not need a pressure bleeder to do this but it is your choice. DOT 4 is mostly used for motorcycles. DOT 3 and DOT 5 are the approved fluids for this use. DOT 5 is a silicone fluid and is not as hygroscopic as DOT 3 but it will still get moisture in it and the downside is that the moisture will go to the lowest points, the wheel cylinders, and rust the bottoms of them. With DOT 3 the moisture stays in suspension and if you flush with fresh fluid every three or four years you do not have that problem. What you describe coming out of yours is either a badly rusted system or mixed fluids. Mixing three and five will form a gel.

P.S. Another issue of a pressure bleeder is finding an adapter for the M-151 master cylinder. You would probably have to make one from a spare cap.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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