M1008 shakes completely when braking

[MrJJ]

Since a couple of day's my m1008 with S250 shelter with grc122 instalation, is shaking heavelly in the back when braking at speeds above lets say 40Mph.
The shaking stops when the car stands still, at lower speeds in town there are no problems.
I have checked if the drum run free and the tension of the lock nuts of the wheel bearings.
Some one a idea where to look or what causes the problem?

 

[Barrman]

Pull the rear drums and make sure the brake shoes are still anchored to the backing plates. Look for anything else wrong while in there and get back to us with more information if you can.

 

[cpf240]

Don't know if this is related, but there was a thread on here not long ago about CUCVs shaking above 40 mph or so, and it was traced to out of balance rear brake drums. Might be something to look at while checking the rear brakes.

 

[MrJJ]

Did read that thread, but think this is realy breake related. all did work fine until a few day's ago.... the car begins shaking from right to left in the back like a idiot at higher speeds when hitting the brake pedal. After the stop the car moves normal again. Going to remove the drums tomorow and looking inside......hope to find the ansewr ...mesage folows

 

[MakersTeleMark]

Drum brakes are annoyingly simple. Odds are that it will immediately become apparent.

 

[MrJJ]

Dismanteled the reardrums today, the right one was totally clean
The left one was full of a kind of grafite like grease ....but it issend that
Could it be that the drum seal is leaking and that it mixes with break dust?
After cleaning the breaks /drum i made a test run with the first brake the car was braking normal at 40 Mph after pulling up again and braking again the car started back to shake.
Think he did it also a littel during the drive back home.
When back home ( let say 6min drive )and feeling the drums they where cold, when feeling the front hubs they feel a bit warm not hot, left some more than right.
Dont know if anny one of you can do some thing with it , but hop to find some idea's where to look brakes, hoses, suspension????

 

[MarcusOReallyus]

Could it be that the drum seal is leaking and that it mixes with break dust?

Yes, that's very likely, and might be the source of your problem.


Time to check for slow leaks!

 

[dependable]

Either slight leak in wheel cylinder leaking DOT 5 or a leak in wheel (drum) seal leaking gear oil could cause brake shoes to bind on drum. After you fix the leak, it may also be easyer to replace brake shoes than get them clean enough for even operation. What ever turns out to be leaking on one side is probably not too far behind on the other. Let us know what you find.

 

[MakersTeleMark]

I'm guessing wheel cylinder.

 

[SouthernSteel]

Front disks that are warped and mud in the rims will do that to. I have experienced that first hand along with an unbalanced wheel which i found so it could be many things keep us posted GOOD LUCK :]

 

[MrJJ]

It are not the wheel cylinders thats for shure , have replaced them a good year a go they are dry and the fluid level in the main cylinder is perfect.
So think it is the drum seal that is leakiing.
Now about 3 weeks a go my front tires are changed can that give trubles when braking at high speed?
Thought it always gave troubles when not good balanced when driving at certen speed

 

[MarcusOReallyus]

If they were balanced, I doubt it's the tires.

 

[MrJJ]

Think after doing some further reading the problem is more than just the break.
It looks that the car has the death wobble, so going to replace the kingpin springs and cups.
And if possibel at once all the front bushings of the stabelizer and spring, they look after 28 years like granny's
Have sended ORD a mail if the would send abroad, because the prices over here are madness in compare to the US
Hope to give a positive end to this problem, there are some more to come like reat springs and fuelpump :S

 

[dependable]

No doubt you checked your tie rod and drag link ends for play. If out of alinement it does not take much play to have a shimmy.

 

[MrJJ]

Tie rod ends are replaced one year ago did had free play, have had a check up last month are perfect now

 

[SPECIALTYLC]

Before you spend alot of time and money on other stuff. Replace the steering stabilizer. Even with all brand new front end parts, if the stabilizer is bad they will get the death wobble. Very common on all straight axle trucks. Especially ones with the King pin Dana 60.

 

[WARWAG]

No tie rods in the King Pin set up.

Make sure you have plenty of grease on hand before you pull the king pin cups and springs. It takes alot of grease. Also why you are there hit the grease fittings (Zirks) under the the knuckle. You may have a greasable fitting in the knuckle U joint as well. Hit that up if you can. There are a few others where the steering arm meets the steering rod ect ect.

Is the problem with your front wheels or your back? Death Wobble is definately a front wheel problem and there is NO mistaking it for the back axle. Now I may be wrong as I am trying to figure this out from reading your description. You say the back end starts to go side to side when your braking. So much so its like some idiot swaying back and forth. At this moment is it your front wheels wobbling side to side or is the steering fine just the rear end going side to side? If its the front then I would say death wobble. If its the back then it sounds like one of your brakes is getting good contact and the other side only occasionally. Keep us posted.

 

[WARWAG]

Before you spend alot of time and money on other stuff. Replace the steering stabilizer. Even with all brand new front end parts, if the stabilizer is bad they will get the death wobble. Very common on all straight axle trucks. Especially ones with the King pin Dana 60.

A worn out steering stabilizer will not cause Death Wobble. Case in point. My stock steering stabilizer has been on my truck for 26 years and it is doing absolutely nothing in the stabbilization field. I just put on 37" tires and still no death wobble. Death wobble usually occures when the pre load on the axle is no longer pre loaded. This can occur when the King pin springs get worn out and or the caps crack/break. This is a simple but messy quick fix for cheap. I believe $36. Even if this is not the real problem at least these are new parts that would need to be replaced anyway if he needs to replace the King Pins and or King Pin bearings. A steering stabilizer is just a band aid at best. They are needed but are designed to be working with a axle in good shape. I was holding out for a Bilstien steering stabilizer but it looks like they dont make one for my truck. Guess a stock one is back on my list.

 

[MrJJ]

The problem first started a short time a go in the back......after removing the drums and finding the left drum smeared all over with a kind of dust mixed with oil.... i cleand it out and sanded the drum and shoes ....have to replace the drum seal for that......after the rebuild of the rear breakes i made a test drive again and found out that the car was still wobbelling like a idiot when hitting the breakes hard at around 40/45Mph....now more in the front....in my opinion starting on the right side only stopping when the car completely stops...when just slowing down and driving on it go's on wobbelling.....as i read other toppics i think the best gues is dead wobbel......so have ordered the springs and cups to day and a seal for the drum going to shop for a HOLE LOT of grease tomorw, hoping to fix the current problems.....Tnx all for all the thinkings and advices up till now...all feedback alway's welcome.....hope to keep the car a longtime on the road in a good shape.......two pitty's the prices of spare parts in europe and the gassolin prices

 

[trukhead]

Did you check the U-joints in the drive shaft? You also might have had a chord separate in the tire or a big booger stuck in the rim or a wheel weight that fell off of the rim.