75 chevy c10
 

Hey guys first post and been itching to get this privilege. I got a 75 Chevy ahortbed c10 with an 8" lift. When I drive it shakes pretty bad. I have read that it could be out of balance tires or the driveshaft. My question is what is it? Has anyone ran across this? It shakes bad and is not normal at all and I need to fix this first. Next is the oil leak that isn't to bad and then restoring the interior. Least to say I got a mudder that a big time hillbilly jacked up from wiring to body

Re: 75 chevy c10
 

Just start isolating different components until you find the vibration. Take note of the speeds and/or RPM's that the vibration is occurring. If you have another set of tires to throw on, do that and see what difference it makes. More than likely a tire or worn suspension parts.

Re: 75 chevy c10
 

The suspension lift is new. Have the paperwork for it. I feel it really happen around 45 so I am guessing it is tires. Now its finding someone that can lift it balance tires and send me on my way. It scares the bejesus out of me. I'll post pics so you guys can see what I got myself into but I think it was worth getting rid of my dodge for this. Gives me something to do and during summer I ride my motorcycle anyways

Re: 75 chevy c10
 

here is my beast. let me list the specs also36 inch military oz tires, cammed 327 with high rise valve covers adjustable rockers. 650 thunder series edelbrock 4 series intake dual headers stright piped to dual 40 series flow masters with a turbo 350 trans and a 3/4 ton running gear. new starter, fuel pump, shocks, u joints, plugs and wires. 4 wheel drive driveline is not hooked up cause I need to get the front pitched so it will connect. tires have about 70 % tread left on them.

Re: 75 chevy c10
 

Its a k10 just remember k means 4x4 and c means 2wd.If the vibration is from the front or back you could try rotating the tires to see if it moves or stays.With a 8 inch lift its probably the rear driveshaft you can use a t case drop kit or have a custom high angle driveshaft built for it.

Re: 75 chevy c10
 

Happens around 45 and front and feels like it is in the cab but I really feel it in the front.

Re: 75 chevy c10
 

I am taking it into Les Schwab tomorrow cause I have no weights on my tires and I think I just need to balance them. Being military oz I hear that just that in fact can cause the wobble.

Re: 75 chevy c10
 

Does it have the stock steering with lift blocks on the arms or is it cross over steering?

Re: 75 chevy c10
 

I don't know. You lost me. I really don't know what that looks like. When I looked it seemed stock

Re: 75 chevy c10
 

Don't know if I beat you to the answer. It has stock sttering from my memory as long as it serves me right. Would it make a difference anyways?

Re: 75 chevy c10
 

Just thinking out loud some people have good luck with stock steering some don't.But getting the tires balance would be the cheapest thing to try first.

Re: 75 chevy c10
 

That's a lot of tire. Plus the fact that they have no weights on them makes that a likely place to start.

Normally - a tire imbalance will start at a certain speed and continue to get worse as you go faster.

A driveline imbalance will normally start at a certain speed and then get better as you pass through that speed range. This is because the driveline itself does not have enough mass on its own to excite the whole vehicle; it needs the synergy of the "resonance" to build enough energy and then subsides as the resonance decreases.

K

Re: 75 chevy c10
 

Well I'll go today to check tires. If its a drive line imbalance how is that fixed? What does it usually cost?

Re: 75 chevy c10
 

I see a few things in your description that concern me.
First is the use of the term "adjustable rockers". All small block chevys (big blocks too for that matter) have adjustable rocker arms...nothing special and not worth mentioning.
Second and most important is the part about the front drive shaft being disconnected. It is no simple natter to address this. You cannot just tip the entire axle up to make it fit. This will result in negative caster. This is a front end alignment specification that will cause handling problems. The truck will wander all over the road and you will be back here posting "how do I fix this?"
Finally, to your actual question, it is most likely tires....especially since you said it starts at 45mph.....but if the tires show any wear at all, I would not "just balance" them. Big knobby tires wear in the blocky tread, so the tires get "out of round".....assuming they were round to begin with.
Take them to a specialty tire place that can do what is called "truing". This is a procedure that spins the tire into a cutting head which will make them round. It has an amazing effect. The tires will balance with far less weight, make less noise on the road, last longer and most importantly....not vibrate.

IMHO, every tire 35" and larger should have this done when they are brand new. These great big tires are never round. I have seen everything from big bulges and flat-spots to tires that are just not concentric to the wheel. Some of the really big ones can be off by as much as 3/4".....and that will shake like crazy. Once they are "true", it's like a brand new truck.

Re: 75 chevy c10
 

Thanks man. Yeah the tires were bought at Les Schwab so I'm taking them in to have them check them. Balance them and make them true cause it is not a light shake. As for the drive line in front I know what you are talking about. I know that wondering thing. I just have to get some shims to angle it and then reattach the drive line. Thanks for letting me know what to tell Les Schwab. It just worries me that this shake is so heavy

Re: 75 chevy c10
 

No, that's what I am saying NOT to do. It will screw-up the ball joint alignment angle and make things worse.
This is an expensive thing to fix. You need to invest in a "high angle" driveline or find a shop that is able to cut and rotate the Cs on the housing to get the caster back after tilting the axle up.
The high angle drivelive is the better way to go. Tilting the pinion upward can starve it for lube, which can shorten it's life.

Re: 75 chevy c10
 

Oh OK. Well looks like I got to go shopping! Whoohoo truck parts! Love it

Re: 75 chevy c10
 

OK update. Went to Les Schwab. They only did rear 2 since front isn't so hot (starting to crack on tire walls) they added a lot of weight and shake isn't so bad. Now to get front tires and have them balanced. I am pretty sure I found the culprit. I look forward to Jeeping you all posted.

Re: 75 chevy c10
 

If the tires are not the root of the vibration I would look at the rear drive shaft. If the lift is too high for the front drive shaft to connect, the back shaft could be at such a sharp angle that it is binding a bit.

Re: 75 chevy c10
 

So had new tires put on today. Vibration is practically gone! The rest is just engine. So now comes redoing seals. The tire shop said upper ball joints were toast so in taking it in to have looked at tomorrow. I have some play in my Pittman arm though which concerns me but for the most part I'm happy. Upper ball joint getting checked tomorrow and Pittman arm. Thanks guys I look forward to putting pictures up on here of everything I do to it