Brake issue 59 2ton

[Softpatch]

I'm having problems with my rear brakes on my 1959 Viking 60
after I drive the truck for a while the rear drums start to drag.

There were all new parts Hydrovac,( vacume asst)
Master cylinder( single)
New Lines,Shoe's, Springs, Wheel cylinder's (2 per side)
at first I adjusted them so they had a slight drag on both rear wheels
and they would lock up after a while
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I backed off the shoe's so I would have no drag still if I drive for a few miles
they would get hot like there dragging.

When I removed the drums and pump the brakes the cylinders move as should
Removed wheel cylinder took them apart and they look clear.
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It's all stock and has the parking brake drum type is on back of transmission
not on rear Wheel's
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I've bled the brakes starting at hydovac then wheel cylinder's
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I'm stumped.......?
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Here's some picture when I first put the brakes together
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Took these Today
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Driver Side
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Pass Side
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[dsraven]

check all linkages in the mechanical pedal assembly to ensure the brake pedal linkage is not sticking or binding causing the brakes to stay partially applied when things warm up. ensure all return springs etc are in place and holding their load properly.
check adjustment of pushrod for the master cyl to make sure there is some end play and that the brakes can fully release
try disconnecting the vacuum when the trouble starts to see if it goes away when the booster is relieved of vacuum. possibly a booster issue? do this after you get home but right away while stuff is still hot. then jack it up and see if the wheels spin freely or not.

[Coupeguy2001]

Check to see that your brake lights aren't on with the truck sitting still after a drive.
If you get the bolt in backwards where the pedal meets the master, the lights stay on, and so do the brakes.
Remember, it is a cam bolt, and if the cam rotates, the brakes will drag.

[Softpatch]

I did not think about the master cylinder plunger The Master is new
will investigate
The brake light switch was part of the floor that was rusted away so I had to shoot from the hip with the stop light switch install.
Light does not stay on the peddle travels about 3" before light comes on.

The front brakes are fine they don't heat up after driving but because it just a cab and frame.... the rear lock up first because truck being lite in the rear
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Thanks will check that out....Sp

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before
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[Softpatch]

brake light switch
Master cylinder
brake peddle height
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[1project2many]

Pedal return spring plenty strong? I've seen problems when driving, pedal bounces slightly and applies pressure to Hydrovac control valve.

[Second Series]

Make sure the brake line is not getting hot from the exhaust causing the fluid to expand.

[mr48chev]

Originally Posted by 1project2many

Pedal return spring plenty strong? I've seen problems when driving, pedal bounces slightly and applies pressure to Hydrovac control valve.

That was my thought too as I don't see the return spring in the photos. The weight of the pedal is probably enough to push the piston in past the return hole and keep fluid from flowing back or the pedal could be sticking after you work the brakes a few times driving. Everything else that you have done is right by the book and I don't see any problems there.

One thing I have seen on cars and pickups with a lot of miles on them is that the shoes will wear ridges in the backing plates on the spots where the shoe rides. The ridges at times enough to cause the shoes to hang up and drag.

I usually slick those spots of a tad with the grinder so the shoes will slide easily on the pads.

[starterman99]

Check if the mster cylinder cap has a vent or vent hole is plugged. Had this on an old f**d years ago. After all new brake system it would drag after 10 mile drive. ajusted and reajusted several times . I back the shoes off then had low pedal . then it sat outside in sun for a little while and the brake lights lit up after it built pressure. the new cap on the master did not have vent hole replaced with the old cap problem solved.

[Softpatch]

The peddle return spring (Heavy Duty) is there on the master.....
just can't see it in the picture's
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I did check the exhaust and ruled that out early..
Checked the spots were the pad's wear on the backing plate..... no ridges.

I played with the brake pad's adjustment for a few hours Tighten spin wheel's.
Trying to bring both shoes up same same for each wheel (two adjuster per)
Loosen spin the wheels..

I'm thinking it got to be drums out of spec's.

Soooo..... going to take the drum to town (tacoma) see if i can find some one who can turn them.
No one in my little burg had Plates big enough to spin them
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Taking these wheels and drum on & off have been a lot of fun...

just tightening and loosening the lug nut is a real adventure.
Hopefuly I can get these drums turned
and stop all this fun I've been having
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[Softpatch]

I did check the new Master cylinder fill lid ..there is no vent in it .?
the old one was cast lid with no vent.?
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[dwcsr]

Originally Posted by Softpatch

I did check the new Master cylinder fill lid ..there is no vent in it .?
the old one was cast lid with no vent.?
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There should be no vent in new cylinder caps, brake fluid absorbs water from the air.

[Softpatch]

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Originally Posted by 1project2many

Pedal return spring plenty strong? I've seen problems when driving, pedal bounces slightly and applies pressure to Hydrovac control valve.

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Originally Posted by mr48chev

That was my thought too as I don't see the return spring in the photos. The weight of the pedal is probably enough to push the piston in past the return hole and keep fluid from flowing back or the pedal could be sticking after you work the brakes a few times driving. Everything else that you have done is right by the book and I don't see any problems there.

One thing I have seen on cars and pickups with a lot of miles on them is that the shoes will wear ridges in the backing plates on the spots where the shoe rides. The ridges at times enough to cause the shoes to hang up and drag.

I usually slick those spots of a tad with the grinder so the shoes will slide easily on the pads.

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.......................................Interesting .?.........................
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I'm thinking the peddle come back to far because I have not installed that cushin
that goes between the peddle rod and the floor a thick gasket rubber stopper
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[1project2many]

I did check the new Master cylinder fill lid ..there is no vent in it .?
the old one was cast lid with no vent.?

There should be a vent. Without it there's no way to account for expansion and contraction of brake fluid. Warming fluid will apply pressure to the wheel cylinders and cooling fluid will attempt to draw air past the cup seals. And yes, this does allow direct contact between moisture in the air and brake fluid. Ultimately this why the rubber diaphragm cover gasket was invented.

In an original cover look for the vent hole in one of the flats of the "nut." Aftermarket covers can have them in several different places. If the vent is present it will be two holes, one drilled through the side and a connecting passage from underneath. The passage underneath is shielded by a baffle. The hole in the flat is probably 1/16" diameter...

[tmoble]

drive it till the rear try to lock up, then crack loose a line or bleeder, whichever is easiest. If there's any pressure at all it's the problem with the relief hole in the master cylinder being covered by the plunger not coming all the way back to stop. after releasing the pressure see if the truck drives normally.

If you bought a rebuilt master it could be missing the internal spring. I personally would not waste any time on the drums. I think you have a pressure build-up happening. Did you replace the rubber hose between the axle and the frame?

[Softpatch]

yes all new lines fitting and hoses.

I did drive it till it got hot then hit the bleader on the rear drum
the "dad" thought that the new Wheel hoses were bad inside which holding pressure
and there was no pressure
I pumped the brakes got out and broke the brake line right at the rear hose No pressure
But they were cold when I did this so this eliminated the MS holding pressure without peddle
with the drums off you could see the wheel cylinders move with a helper pushing the peddle
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As i was adjusting the rear brakes I could feel the wheel binding in a spot
while turning the wheel back and forth on jack stand
which made me think maybe the drums were egg shape and why they would get hot
and lock up....


the brakes would work in the dirt when cold but after driving them they would get hot and feel like they were dragging even though the brake peddle was not applied
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I hope it was just the drums getting hot because I could not adjust them properly being out of spec's
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So went to the big city
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found this place
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they had stuff there
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they said they would need the hub to turn them went back home as a was taking the ferrie home
saw this
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pulled the hub off the truck and headed back to tacoma
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back at the shop
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about hr and $250 we got this and two rear seals
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back home again puting the rear axle back together
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[Softpatch]

Just went out to look at the old MC look for a vent on the cap
sure enough found it....
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out to the truck
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new mater found it also had vent
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[dsraven]

too bad I didn't see in time to mention that you need the hubs to machine the drums properly. oh well, done now. it is also a good idea to mark the drum and hub with marker or crayon so they go back together in the same orientation.
if you have a single brake system, which applies front and rear brakes together and also releases them together, then if it is a pressure build up in the system ALL the brakes would drag not just the rears. correct?
have you checked the adjustment on the pushrod for the master?
have you checked the pedal for bouncing as you drive, possibly not allowing the master to release pressure back to the reservoir?
try a really strong spring on the pedal return so there is no question the pedal is staying where it should when the brakes are released. if that fixes the issue then it is a bonus, and cheap too.
does the cab flex on the mounts enough when driving so the linkage could bind and not allow full pedal return sometimes?
the pedal arm has a rubber bumper on it to stop upward (return) travel at a given spot. is that in place and does the pedal sit against the stopper when brakes are released?

[dsraven]

forgot to mention, usually guys will squirt some gear oil into the hub before the hub nut goes on, that way the hub bearings won't be dry till enough corners are taken to spill some gear oil down the axle tube for bearing lube. personally I always overfill the diff and jack it high on one side for a minute, then the other side for minute, so the hubs always get positively filled. overfill the housing and let it sit level, overnight if possible but at least for a hour or so, then check the fluid level in the morning. you only wreck one diff housing before you pay better attention to hub bearing lube.

[_Ogre]

if the front cab mounts are shot they can depress the pedal a little since the mc is frame mounted
remove the pedal/mc bolt, it should go back in without depressing the mc any
if it won't go back in shim the front of the cab and try reinstalling the bolt

the cutouts around the brake and clutch pedal holes indicate this might be the problem
another bad cab mount indicator is doors hanging up on the front fender

[Softpatch]

I have to go to work will be back in a week to give you an update
thanks for the info good stuff about the
peddel stop, mounts,
Oiling the axle bearings
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[1project2many]

then if it is a pressure build up in the system ALL the brakes would drag not just the rears. correct?

Depends on the size of the wheel cylinders, shoes, and springs. They usually bias the fronts higher but who knows on an old rig that may have been special ordered...

forgot to mention, usually guys will squirt some gear oil into the hub before the hub nut goes on, that way the hub bearings won't be dry till enough corners are taken to spill some gear oil down the axle tube for bearing lube.

That's how we do it. That way the guys that have no patience don't have to wait for oil to roll down the axle tube. One thing for certain: Never grease the outer axle bearing. The grease can prevent oil from getting into the hub.

as a was taking the ferrie home
saw this

There ya go... you've got a problem with the seal.

[_Ogre]

that could be a seal of approval

[55dude]

you went to the right place to get the drums checked and turned, they can build you damm near and brake shoes or custom clutch setup. in the 35 years i have used them they have never told me they couldn't do it!

[Softpatch]

Originally Posted by Softpatch

I have to go to work will be back in a week to give you an update
thanks for the info good stuff about the
pedall stop, mounts,
Oiling the axle bearings
............................................Sp
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Wow.... I sure dropped the ball ....

Lots has happened in the two months............... (this yr)
still have not resolved my brake issues....

"Life"
Through a Couple of knuckle balls at ya
the Viking just didnot seem that important in the big pictures
I heeled up pretty good now
wanting to injoy this truck More.....
and drive it
SSssssooooooo pushing it back on top....

Needs some help (again)

Drove it a couple of times having to pump up the brakes
I have checked the pedal return clearance Return spring as you suggested
Does have plenty of room and is Not hanging up before returning fully...
good call BTY
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Now I cant keep pedal pressure I can pump up the brakes
and they work a can feel the rear drums grab let off pedal
the shoes release but the pedal will loose pressure..?

Takes about ten pump to pump up the pressure
The master does not seem to want to hold the pressure
while bleeding the brakes let off the pedal remove MC cap... fluid will shoot out of the reservoir. Vigorously
( no pictures)
and thats why I can't have nice things
..... Once ok but three times
Probably shouldn't admit to that.

Like it's air bound .?
but i know that can't be I pushed two quarts through the whole system
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I can't help but think maybe internal But it worked fine up in till I drove it to inspection 30 mile in & Heated up the rears
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getting old sux
07-21-16

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R.I.P Mark 07-27-56..06-13-16..miss you............................. best bro ever
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