Re: [Amc-list] enclosed driveline

[Frank Swygert <farna@xxxxxxx>]

What you need to do now is move the rear axle back 4-6 inches. You can't do this with the car sitting on the rear wheels. Don't let some old time mechanic tell you to "jack" or "pull" it back either -- that worked on 50s Chevies because they had leaf springs with a torque tube axle. 

Find a spot the car can sit a while first. Jack it up, preferably with a floor jack under the rear axle sticking straight in from the rear (make sure the floor jack is on solid surface so it can roll back -- a board if in dirt). Put jack stands under the body right in front of the rear wheels, and take the tires off. Now disconnect the shocks, the panhard rod at the body (wire it up to the axle), the rubber brake line (this is a good time to replace it if it's never been replaced before, cut it if replacing), and the park brake cable from the front (wire it up to the tube for now). Let the jack down and the springs should fall out. If not, jack it back up and put the jack stands a little higher and try again. 

Once the springs are out, the entire rear axle will push back. It's been on a long time and may take a good push to get loose. Chock the front wheels good then push or pull hard on the rear axle. It shouldn't take too much pressure, I've sat under the car and kicked/pushed hard with my legs to get one off (ONLY if you have really good jack stands and chocks on the front wheels!). It will be safer to loop a rope or strap around the axle and give it a good jerk from behind the car. The tube will pull off the axle and out of the trans and hit the floor, so make sure you have a block of wood or pad under the front. The drive shaft should pull out of the tube from the front. You will likely need to unbolt it from the rear axle and pry it forward, as the rear slip joint is probably stuck from age.

I'm assuming you have a V-8 car since you have a problem. Those have a double-cardan constant velocity joint (two standard cross joints with a special carrier). That particular joint was only used 4-5 years in AMCs and Lincolns (that I know of). There is a spring-and-pin centering device in the middle carrier that wears out. There was once a repair kit, but since that type joint hasn't been used in over 40 years it is no longer available. Blaser *might* have a repair kit available (www.blaserauto.com), but I wouldn't be surprised if he's sold out. 

Fortunately the front half of the V-8 driveshaft is tubular. That makes it an easy fix by a driveline shop. They can get a new type CV joint for the front. The splines on the BW M-8 and M-1x trans is the same as the venerable T-10, so they can get a new yoke that will work. The old CV joint can be cut off and the end of a new type welded on. Of course the CV joint isn't really required -- pre 63 V-8s used a single joint. The driveline shop can lengthen the tubular section and weld on a single joint. The CV joint is slightly smoother, but the six cylinder cars used a single joint and I never noticed any vibrations. 

If you have a six cylinder car the problem can be one of two things -- a worn universal joint or a bad center bearing. The sixes used a solid shaft roughly an inch in diameter (going from memory on the size, maybe a bit larger). To prevent flexing a carrier bearing was mounted in the center. The u-joints typically last well over 100K miles due to being protected from dirt. The center bearing does too, but if the rear seal in the trans has developed a leak (the protected rear seal also lasts a long time, but can get hard when parked for a long time or oil is over heated) the oil can break down the rubber casing on the carrier bearing. If the u-joint is bad replace it and put the thing back together. If not, pull the shaft (the u-joint end slips off with the shaft remaining in the tube) and inspect the bearing. The bearing will slide off the front, but will be stuck I'm sure. The usual suspects (Blaser's, Galvin's -- www.ramblerparts.com -- or maybe other AMC vendors) may have 
 a replacement bearing. If not, check with Inland Empire Driveline Service. They sell a lot of different center bearings, and may be able to match something up or modify one to fit (http://www.iedls.com/page11.html). A bearing with the proper inside diameter and a urethane casing (such as their "High Impact Polyurethane Cushioned Center Support Bearings") can be trimmed to fit the diameter of the tube once the metal bracket has been removed. They may need the old bearing and/or an accurate measurement of the tube inside diameter to find a replacement. 

--------------
Date: Fri, 20 Feb 2009 00:46:09 -0600
From: jason patrick <mrrumblur_jasonpatrick@xxxxxxxxxxx>

I've got a '65 Marlin that has a bad driveline vibration at speeds above 40 mph. I plan to replace the joints and have unbolted the tube. I'm not positive what the next step is. Does the diff need to swing back to allow removal? If so, how far back? Thanks in advance.
 

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)


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