fun with Brakes

MrTube

MrTube

Well-known member
Hey, Our 31 pickup is having some brake issues. I'm going to be adjusting them soon which should fix most of the problems. however there is one symptom it has that I am unsure of.

The drums and shoes were sent out maybe 10 years ago. I am unsure of what was done but I believe we paid over $2K for the job. I seem to remember mention of them cutting the drums and matching the shoes to them?? At any rate, there are very few miles on everything and one of the front wheels is very grabby in spots, it feels just like a badly warped rotor except.... its a drum :)

I'll be pulling the drums off in the near future to inspect everything and then will proceed with adjusting. We have driven the truck around 150 miles thinking maybe its just from sitting but it has not improved.

Like I said, 3 wheels feel fine just one pulses\shakes just like a warped rotor would.
 
Is there any chance play in the front axle combined with unbalanced front brakes could cause this kind of reaction?
 
Mr. Tube,

Which wheel pulses? I had an unusual problem several years ago where a pulsing upon stopping was actually a rear axle failing and the drum starting to move around. I figured it out when it failed completely.

Charlie Stephens
 
How is the kingpin? If it is loose the brake will grab,then as the kingpin moves it will loosen,then tighten,then loosen again.Usually when they are like that they will quit the gyrations if you stomp down hard and hold the pedal down.I had a tudor come here like that,you had to treat every stop as a panic stop unless you wanted the pedal to beat the bottom of your foot.I have also had the old style floaters do that,the type with a pin through the wedges.They generally did that after the car had sat for a while and the rust on the drums was grabbing the linings.I would ride the brakes out of my driveway,(700 feet)and I would be fine until the car sat around again.
 
Will check the kingpins when we jack it up. The only thing that comes to mind regarding that is the passenger side has quite a bit of positive camber as if at one time it possibly slid into a curb hard or something.

I had checked most things out in the front, but I had weight on the wheels so I probably wouldn't have noticed slop in the kingpins.
 
Mr. Tube,

Are you running stock wheels and stock mechanical brake drums? Running later solid wheels without the proper spacer might be warping the drum. Running stock wheels on hydraulic drums will also require a spacer (different spacer, same idea). Running wire wheels on hydraulic drums without the proper spacer might be warping the drum.

Charlie Stephens
 
You might also check the drums with a micrometer.
The steel drums were originally .145" thick.
Safe wall thickness is .120".
Thin drums cause brake fade.
New CAST IRON drums are .270" thick.
This is not particularly related to the pulsing, but you should really check your shoes and drums visually and by measuring their "meat' before you just go adjusting things.

This will help you realize what you got for the $2000 brake job, and what you must do to get the brakes into an acceptable condition. Just tightening up on the adjustors might not help in the long run.

Pulling the drums is (usually) no big thing.
 
Bruce : I wouldn't be surprised if the drums are cut way out of spec. The guy our company had maintaining the 'A' messed up just about everything he touched.

He had the timing set to what appeared to be around 20 or 30 degrees ATDC. The truck wouldn't even run with the timing lever all the way up. And it chugged when fully advanced.

One if the first things I did was set the timing by ear (didn't know the proper way to do it at the time). Later on I still had some trouble setting it the proper way but easily got it spot on with the help of members here.


How hard are the kingpins to do? should I start taking tums now or wait? :)
 
When I first bought my 29 Tudor it had pulsing brakes. That's because someone let the right rear wheel fall off and the backing plate was ground flat on the bottom and the drum was bent just enough to pulse.
 
Mr. Tube,

Kingpins are not hard to do. Don't get sucked into buying a kingpin reamer. A local machine shop can do them with a hone probably cheaper and definitely better.

Charlie Stephens
 
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