C6500 Front Wheel Bearings

[Daelus]

Took possession of an older fire apparatus built on a C6500 today and noticed some pretty bad vibration approaching 50mph. Backing down to 45 smoothed everything out and I was able to make the two hour trip home without issue.

This truck only shows 17000 on the odometer, and I have reason to believe that its accurate based on the overall condition, but it also could just be a well maintained piece that has rolled at least once.

This isn't my first motor fire apparatus, but it's definitely the oldest in my collection. What I'm learning is that also might make it the hardest to find parts for. Parts for the apparatus are easy enough to come by since emergency one and hale are both still in business and put these setups on a ton of trucks through the 90s, but the truck itself is not well catalogued.

I expect most of the wear items have given up and the bushings, shocks, and bearings all need to be replaced. But I also don't want to tear it apart without having some level of confidence I'll be able to find some parts to put it back together. I know there are quite a number of these trucks still in operation as grain haulers, so when I was initially looking I figured they had to be getting parts somewhere. I figure there's a possibility someone familiar with this era might be able to look at this and tell me I can cross reference a different chassis or find parts some other way.

I think the immediate need here is to re-pack the hubs with new races and bearings and replace the shock absorbers and rubber leaf spring bushings before getting everything balanced and aligned. If anyone could help me find the part numbers for some of these things I would greatly appreciate it.

If there are any images that would help identify the axle/hubs/whatever I'm more than happy to go out and take a few pics.

 

[bucket]

Where do you feel the vibration the most? The seat, the steering wheel or just the truck itself? Vibration is normally caused by tires or driveline.

 

[rusted nuts]

I don't replace any bearings unless they are wore out I feel the older ones are a better quality than the new stuff.

 

[squaredeal91]

I did rear brakes on a 78 c50 3 years ago and was able to get everything at Napa. Wheel cylinders and hardware was ordered but the shoes had to be sent out and re-shoed.

 

[Daelus]

Where do you feel the vibration the most? The seat, the steering wheel or just the truck itself? Vibration is normally caused by tires or driveline.

It starts in the steering wheel, the rest of the truck follows to create a wobble effect through the whole chassis. There's a little bit of play in the pitman arm, but otherwise it all feels tight. So you're saying I should start with balance/alignment rather than trying to dig into the carriers?

I did rear brakes on a 78 c50 3 years ago and was able to get everything at Napa. Wheel cylinders and hardware was ordered but the shoes had to be sent out and re-shoed.

Appreciate the information, I'll see what those guys can do for me. Did they have a way to lookup parts for a c50, or did you have to give them a cross reference?

I don't replace any bearings unless they are wore out I feel the older ones are a better quality than the new stuff.

So leave well enough alone? They aren't squeaking or grinding, so maybe that's the right move here. Just trying to get out of the risk of a death wobble.

 

[squaredeal91]

after screwing on computer I think he got a book and found everything But he had to have samples. Does it have bias tires? They develop flat spots that can takes miles to smooth out. Odds are its not bearings with those miles.

 

[rusted nuts]

It starts in the steering wheel, the rest of the truck follows to create a wobble effect through the whole chassis. There's a little bit of play in the pitman arm, but otherwise it all feels tight. So you're saying I should start with balance/alignment rather than trying to dig into the carriers?

Appreciate the information, I'll see what those guys can do for me. Did they have a way to lookup parts for a c50, or did you have to give them a cross reference?

So leave well enough alone? They aren't squeaking or grinding, so maybe that's the right move here. Just trying to get out of the risk of a death wobble.

I would start with the little bit of play in pitmman arm then look at all the joints for play

 

[618Syndicate]

NAPA is where we get most medium duty (F550/F650/3500HD) truck parts from for the wrecker service I moonlight at.

 

[bucket]

It starts in the steering wheel, the rest of the truck follows to create a wobble effect through the whole chassis. There's a little bit of play in the pitman arm, but otherwise it all feels tight. So you're saying I should start with balance/alignment rather than trying to dig into the carriers?

Appreciate the information, I'll see what those guys can do for me. Did they have a way to lookup parts for a c50, or did you have to give them a cross reference?

So leave well enough alone? They aren't squeaking or grinding, so maybe that's the right move here. Just trying to get out of the risk of a death wobble.

That sounds like tires causing the shake/wobble/vibration. Ancient bias ply tires I assume?

I don't know about all Napa's, but many deal with medium and heavy truck parts as well.

 

[Turbo4whl]

Wheel bearings, races and seals all have the manufacture's part numbers. The bearings are mostly cataloged the same between different manufactures with some having different prefix letters. The seals, not as much.

Hard to see but some seals have the part number very small molded in the rubber, most have stamped numbers. My suggestion is to remove the bearings, clean and inspect and if you need to replace them, you have the numbers. You will need to pound out the races for the numbers, but if they look good leave them in.

There are also some model medium duty GM trucks with barrel bearings. To remove the inner bearings, not only do you need to remove the seals, but also the inner races.

 

[idahovette]

I'm with @bucket ....tires first