micjman

I have a 12/71' 240Z I got a few months ago in bad shape. I had the engine rebuilt and now its runinng strong. I've just bought one of those bushing kits and a new rack and pinon for her to tighting things up. I got this problem clunking? sound comming from the rear of the car. I originally assumed this was a U-joint, because it seems to clunk when I first get moving and slow down to stop. Anyway, talking around, I found out that there is a rubber differnetal mount piece? that wears out. Has anyone done this replacement and do ya guys think it's my problem? Also my fuel gauge is not reading, do you think it is more common for the meter or sending unit to be the problem?
Thanks guys I love Z's but am new to this game.
-Mike

theramz

If you raise the car so one wheel is off and in gear, you can have someone rotate the tire back and forth while you observe any movement of the suspension/drive line. As for your fuel gauge it's most likely the wiring somewhere between the tank and the dash. Advise getting a book or two.

texasz

Clunking:

Climb under the car and grab the half shaft and rotate it back and forth if there is play in the u-joint you will see it (repeat this for both sides of the car and the drive shaft). If there is play in any of these then replace the u-joints (I highly recomend Spicer u-joints which can be purchased from MSA).

If this is not the source of the clunking then it is likely the front diff mount and or the arrester strap. Should this be the case you have a couple options. Search hybridz.org and classiczcars.com for some great homebuilt solutions to this, or buy a solid front diff mount from somewhere like Arizona Z Car, or just get a stock replacement. I suggest that you search both these sites and do some reading before making a decision as to which solution you choose to implement.

bjhines

A billet mount will crack the differential crossmember... Do not use it alone!!!

unless it is used with a SOLID rear differential mount that replaces the leaf spring mustach bar ENTIRELY... That little billet mount is only part of a much more complicated system to mount the differential... The people who sell those only copied the easiest and cheapest part of that mounting system...



These pics don't do the damage justice... I will get some more shots of the Dozens of radial cracks around every bolt hole... These pics show one of the cracks that had progressed entirely through the upper stamping of the differential crossmember... This was used on a track car for 5-6 years... the suspension uprights were the Suspension Techniques versions with the integral swaybar mounts... the mustache bar was mounted with the suggested polyurethane Eye bushings... The differential was a NISMO R-200, 3.54 ratio... the engine used was an L-28 with triple Weber carbys....

bjhines

on another note....

A very common clunk also comes from worn out Mustache Bar to differential stud HOLES.... the middle pair of holes on the mustach bar can get enlarged sometimes(loose rear mounting nuts)... you can try removing the nuts and washers.. replace the hardware, check the diff. cover studs to be sure they are tight, redrill and bush the holes to fit the studs tightly... I would just try cleaning and retightening the harware first...

redneckz

I had to take my gas tank out for cleaning. When I put it back in I put the wires on backwards and it didn't work. After I drove the tank dry, I looked into the problem and found the crossed wires. I reversed them and it worked. Hope that helps, Rich.