Differential problem!

[boardwar]

Hi all, and thanks in advance to all responses. So I've got a little bump coming from the rear of car when shifting from rev. to 1st and back and forth. I isolate the sound to the right side half shaft and determine that the center flange bolt could be loose. I disconnect the 4 flang bolts where the half shaft bolts to the side flange and sure enough the center bolt was loose. So I get the Haynes manuel out and it says on page 126 the center bolt should be torqued to 50 lbs/foot. Well I grab the toque wrench start cranking it down and snap I now have broke the center bolt with the majority of the threaded end still in the flange. Upon removing the differrential plate for futher inspection I found that the center bolt has bottomed out against the pin that holds the spider gears. So far I've drained oil, removed differential, removed ring gear, drilled broken threaded end and attempted removal with screw extractor, no luck. Any suggestions would greatly be appreciated. I believe the Haynes manuel is incorrect on torque specs, there is no way imo the bolt should contact anything in diff. I have a 71 240 all stock inc. r180 w/3.36:1. Thanks again.:disappoin

[d240zx2]

Weld it out. Using a high strength electrode like Eutectic 680 or MG equivalent, weld a nut onto the extended broken bolt. Allow to cool, then back it out with a wrench. Works every time it's tried.

If the broken portion is below the surface, use the electrode to rebuild the missing portion of the bolt. Use a "dabbing" technique to minimize heat build-up and to avoid molten weld metal from rolling over and adhering to the casing. When sufficiently lengthy, the nut can then be welded onto the reconstructed portion of the broken-off bolt and it'll come out quite nicely.

Edited August 16, 2009 by d240zx2

[boardwar]

:)Thanks soo much, excellent tip, worked great! Now for a new bolt w/ proper torque. I believe that someone on here suggested 13-18 ft/lbs. Guess I'll start with that and see if it works there. How about torque for ring gear bolts? Thanks for help, this site and the knowledge here is great!

[boardwar]

Thank you d240zx2 for the tip. I was wondering also what the paint code is on your z? Is that safari gold? I will be repainting mine this winter. Looks to be the same color, but I can"t make out the code on the sticker. Thanks again.

[d240zx2]

Paint is Nissan 920 Gold, with a handful of gold metalflake tossed in for good measure. That's the original color of the car, just making it look a bit late '70s rather than early '70.

Glad the welding tip helped. That procedure has saved me hundred$$ over the years.

Wherebouts in Oklahoma? I grew up near Lawton.

Frank

[jmortensen]

You might want to search "differential clunk". I think you're barking up the wrong tree trying to tighten the stub shafts. Probably a mount, a bushing, or a U-joint.

[boardwar]

Thank you for the color code tip! I thought that was the code from the research I've done, but wanted to confirm. I live in Spiro,Ok. It's about 10 miles west of Ft. Smith, Ar.

I certainly appreciate you, Mr. Mortensen, for the added suggestions. I have read a great deal of your posts on here and very readily acknowledge your expertise. I have done several very thorough inspections of the previously mentioned components and cannot find any slop or signs of slack in the rear of car elsewhere.

I must admit this little annoying sound has been driving me nuts! I want to again say "Thank you" for the responses. However, since buying the car a few weeks ago I have been up in the air over which direction I want to go with the car. The PO had installed a jasper reman long block w/less than 1000 miles when I bought it and rebuilt just about everything on the front end of the car including tranny, clutch, front struts, ball joints.tr ends, sway bar bushings, and several other misc parts. The car is virtually rust free with about 70 percent original paint on the car. I bought it from an elderly gentleman (83) from California. Well I have finally come to a decision and found an 83 non turbo/ 5 spd. for a parts car complete with entire drivetrain. From all the reading I've done on here the past several weeks, since the 240 purchase, this seems to be one of the prefered cars for upgrading components. So, since the diffy is out already, it will be first to swap along with any and all bushings, ujoints, struts, etc. My goal is to build a very good perfoming street car that the orginal drivetrain could be reinstalled, should the need arise. I'm aiming for 275ish at the 2.8l crank, coupled to the t5 w/the 390 gears. Suggestions for this would be greatly appreciated! My funds aren"t endless but I do have a substanial amount set aside for this project(@7g). Once the drivetrain is complete and performing to my expectations the car will undergo a complete restoration concerning the body and paint. I do own a body shop after all:)

[doradox]

Stub axle nut not tight enough is often the cause. You can check by raising the rear, put on the parking brake, and use a long bar stuck into the rear u-joint of the driveshaft to apply torque. If a stub axle nut is not tight enough one of the half shaft flanges will "slip" just a little when you enough apply torque. Reverse the torque on the drive shaft and it will pop back.

Steve