Thread: Drivetrain Vibration Identified

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With you guys pointing me in the right direction, I crawled under the Model A after work tonight and the problem causing the vibration is obvious. The transmission points slightly down, and a straight line from it would hit the ground a little behind the car. Rear end also points down, tho' not as much, and a straight line from it would hit the ground in front of the car. Driveshaft is 22" long, including u-joints, and trying to sight along it while laying under there, it looks like the u-joints may not be perfectly aligned, either. Oh, S.O.B., what a mess. Do you guys think a CV joint would help ?? Driveshaft would have to be cut, but then they could align the u-joints, and balance it, too. The way the thing is set up, I hate to try and cut the rear end loose and re-weld it, and the engine/trans are way back in the frame and I doubt if I could lift the tranny. In 6 months or so, I hope to put a proper custom frame and running gear under it, and move the engine/trans forward where they belong, but I'd like the use of it till then. Whaddaya think ?? Starting to wish I'd never bought this thing. I haven't found ONE thing so far that was done properly - in the whole damned car ! ! ! What a mess.

Disgusted Lar.

You wil have to change the rear pinion angle. Do a search...this has been discussed in detail before.......Don

Here is a good primer on driveshafts and u-joints. Tom builds nice stuff.

http://www.4xshaft.com/techinfo.html

If your rear end (in the car) is leaf spring supported, you can use shims to change the angle. Shims are a wedge shaped piece of steel that go between the spring and the bracket on the axle . They are retained by the U bolts. CAUTION!! Support the car, AND the axle when you unbolt the axle.... dont be like the cartoon character who unbolts the axle and lets the car fall on him.

Shims are available in different angles.

It's a coil spring rear. From previous experience with the welders around here, it's prob'ly gonna be a $2,000.00 welding job. Buncha thieves. I'll hafta try and find someone else. Where would I look in the archives for previous information ?? My main concern in welding on the rear axle is burning the oil inside the axle and winding up with chunks of carbon floating around. Is that a real concern ??

Hmmm........thanks, Robot.........shoulda read over that web site 1st. Lots of good stuff there. Don, looks like you're right - looks like I'll hafta bite the bullet and start cutting that rear end loose. Sigh........

Lar.

You need to be concerned with tweakin' the housing with heat from the welding. Make sure you use someone who knows how to keep it straight so you won't have bearing issues later on.

It appears to me as how your only choice is to cut and reposition the rearend. If you don't have a local shop that you trust, try Total Cost Involved, in Ontario; a bit of a drive, but not bad considering what you are taking on. They are a full service rod shop, and have a good reputation. Here is their site URL:

[URL=http://www.totalcostinvolved.com/]

There are several other specialty rod shops in the Inland Empire, as well; do a little digging online, and I'm sure you can uncover a few Good luck.

Here's another one:

http://www.nolimit.net/

This is No Limit Engineering, in San Bernardino. Check 'em out.

lar, you sound like a guy with a lot of enthusiasm. Good for you. Also, it sounds like you're getting a little thin with the issues you keep posting about this car.

I don't know how to say this without it sounding harsh, but that's not my intent. I've been watching your posts for the last few weeks and this car sounds like there's almost NOTHING done right on it. Based on what you've been posting you're going to be spending a ton of money and two tons of time trying to make a silk purse out of a sow's ear.

If you haven't gotten too deep into fixing a bunch of this stuff why not sell the thing off to someone else. Chalk it up as a learning experience and go out into the for sale world having given yourself an education. Now that you've learned what some of the pitfalls are, you'll be a better informed and more selective buyer the next time. Trust me, it'll be cheaper, and you should end up with a better car.

Well that's something else for me to worry about since I don't have my car running yet. So what is the main cause of the problem, the short driveshaft? My driveshaft is 34" long not counting the splined parts at each end and it looks like my drive shaft leans down at the back by about 10 degrees with the rear input and the trans tailshaft about parallel to the floor. But my weld-in 8" rear has four bar links so if I have to adjust the angle I can play games with the adjustment nuts on the four bar shafts by about +/- 5 degrees????

Don Shillady
Retired Scientist/teen rodder

OK, here comes the "instant expert" to tell ya how it's done. :-) (definition of an expert - an "ex" is a has-been, and a "spurt" is a little drip under pressure) Take a look at the web site recommended by Robot, above. It's laid out very clearly there, with diagrams and all. A *most excellent* site.

Educated Lar.

To Bob Parmenter: No offense taken, and I clearly see what you mean. You understated it - there is NOTHING done right on that S.O.B., but now it's MY s.o.b. :-) Actually, I've thought of just what you say, but it would be a 50/50 chance. I got the car at a good enuf price that I can spend quite a bit on it and come out about the same. I had thought to use it as a daily driver while I fix it up, and I've almost got it to that point. Main thing is the time frame. Instead of a quick clean-up, I've had to put it on the back burner so I can finish building the 2 seater airplane I've been working on for several years. It's *almost* ready to fly, and I anticipate 1st flight this fall. Also, I just can't ignore my faithful little center console boat that I'll be taking on a fishing trip to Puertocitos, Mexico in just over a week. Once the car is safely driveable - soon, now - other things will take their rightful place in my time scheduling. BTW, that airplane - a Kolb Mk III - also reflects hot-rodding. The engine is a highly modified VW 2110cc that I built myself, and has all the goodies, plus wasted spark ignition, electronic computer controlled fuel injection, hi-vo chain reduction drive, etc. I do like my toys, and being well over 60 just intensifies the addiction.

Tough it out Lar.

A couple of days reflection on this, and I was just out there starting to prep the boat for next week's trip. Got to looking at the car, and ya know, I don't NEED another high dollar, long term project. If I'm stuck with it, so be it, but it might be a good idea to see how much of my money I could get back out of it. Gonna take a look at the For Sale page, I think.........

Lar.