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my jeep is starting to vibrate quite a bit. This doesn't seem to happen all the time, it varies with the roads I'm on, but it is the same on the same roads. They might be because the roads are rougher, but they are not that rough, and I've been on them with other vehicles and not had a problem. Is this a suspension issue? Also, with the steering wheel, I notice that it gets really stiff on sharp turns when i have it tightened up to allow 1 inch or less of free play. If I have it looser, it's not a problem, but there is too much free play, and the vehicle wanders more on the roads. Any suggestions?

Get an experienced mechanic to ride along with you! He will be able to feel any suspected anomalies and actually feel where they are coming from.

Again you offer up a problem with no history. Is the vibration a completely new thing. Your wording is unclear on weather the vibration is on all roads or just some surfaces. Is the vibration felt at the steering wheel, the pedals, the floor, your arse or where? If this is a sudden new vibration then what maintenance have you performed recently to the steering system or suspension. Have you already checked wheel balance, king pin wear, steering linkage wear, drive shaft spline or U-joint wear and wheel bearing play?

I recall discussing your steering play before and it was explained then that the worm is not the same diameter it's entire length, that you make the adjustment with wheels straight ahead/centered and that excessive wear of the cam or worm will result in an eventual inability to adjust enough in the middle to eliminate play and still have free steering to the stops in both directions. If you have made the last centered adjustment correctly and it is to tight in full turns then you only have a couple of options.
1-Loosen it up at the center and live with the wandering.
2-Leave it adjusted correctly for no wander and live with the tightness in full turns.
3-Buy a new cam/worm.

Please try to keep your reply organized to address each question.

I don't know of a mechanic in the area that works on vehicles this old. I keep running into that problem in Philly. I had no problem fining them in Maryland and Texas.
I haven't had the vibration before. It wasn't present when I drove down to Maryland a few weeks ago. I have noticed it way more on some roads than others, but it seems to be always present once I hit about 45. I have tried switching between direct drive and overdrive, and the problem is the same.
The vibration seems to be everywhere in the body at once, not just confined to the steering wheel or seat. If anything, the pedals and floor have it the least.
The latest maintenance I have performed has just been to swap out the transmission and transfercase oil. I did use Lucas 10002 Heavy Duty Oil Stabilizer. I first used it with the Lucas SAE 75-90W oil. I used it again with the new non corrosive oil, and the vibration seemed a little less. Shifting was easier too. I had wheel balance checked, and replaced the kingpin bearings, wheel bearings, and U joints not too long ago. I replaced the entire steering assembly (box and stem) with a NOS one from John at Midwest Military like 800 miles ago.

The new info you provided really offers us no new insight to your issue. Let's go back to my first suggestion. Since you don't know a mechanic who works on old cars in Philly I still suggest you make the effort to find one.

You can attend local old car shows and ask around, you can hit the yellow pages, and I even hit google with a search for: "antigue and classic car repair philadelphia" and got 800,000 hits!

I was born and raised on the Jersey side of the Ben Franklin bridge and I knew at least 50 shops there in the 60's when I was wrenching in that neighborhood.

You're right Wes, I didn't see the forest for the trees. I Google searched and found one near my work. I'll stop by tomorrow.

These old military jeeps don't drive or feel like a modern car. What you are feeling in terms of wandering and vibration may be the "normal" for your jeep. My M38A1 tends to buzz a bit at higher speeds but the M38 is smooth as silk - differences in transmission wear and perhaps flywheel synchronization may be my issues but it's not bad enough yet to tear into the A1 to find the cause. You mention tightening and loosening the steering but there is a procedure in the TM's for setting pitman shaft pre-load as Wes mentioned. See page 299 of TM-8015. If the vibration is noticeable at higher road speeds, check to make sure the tires have been balanced. And if they have been balanced, check to make sure you haven't lost a weight somewhere - it happens.

Bought a car out of Oklahoma once that had this
problem. Put it up on the rack and found that there
was caked mud on the inside of the wheels. The mud
was only on one side, and about an inch thick. Washed
it out and the problem was solved. Worth a look.

Jim in Darkest Arkansas

Thanks guys. I'll stop by my buddies shop, put it on a lift, and check it out.

Cow Town, NJ! I should add one of my favorite places!

The NJ MV clubs are very active. An early jeep mechanic should be fairly easy to find.

It would be a bit of a drive but Daryl Bensinger is not too far away from Philly.

Also, Army Jeep Parts is almost right in Philadelphia. If they can not fix it no one can.

NOT FOR NOTHING BUT I WOULD SAY YOU GOT A BAD U-JOINT

It increases the value of these boards when we follow through with the solution we found to our problems.

U-joints are fairly new, and I put heavy duty ones on. One did fall off while I was changing the speedo drive gear, but I picked it back up, cleaned and put back in the two pins that fell out, and it should be fine. Wes, I am taking the M38A1 to the local classic car place for an alignment on Tuesday, i have an appointment, and I'll post results then.

Oh, and I've been meaning to head out to Army Jeep Parts, I think i will this week.

wesk wrote:It increases the value of these boards when we follow through with the solution we found to our problems.

You are so correct Wes & this aspect is sorely missing from most sites/boards.
In AU it's called I'm all right Jack.

Alright, the toe in was corrected, the tie rods were not angled quite right, and one of the washers from the steering stabilizer was catching the end of a tie rod. The steering box needed the adjusting screw tightened like 1/4 of an inch. I had tried it before, and one side always bound up while turning because apparently the tie rods were not quite at the right angle. The guy at the shop pumped up the tires from 25 TP to 35 for adjustment. He said I can bring it down, although the jeep seems more energetic and a little firmer with them inflated.