View Full Version : Rear Axles 1st Gen

07-08-2002, 10:54 PM
1980 Rx-7 running disc brake rear. Supposed to be a "Small Axles" Ordered the Bearing Kit from Mazdtrix. Pulled axles to replace seal found that the wheel bearings are larger than in bearing kit,retaining ring tacked to axle, Splines on one axle twisted but now I don't know what to get for parts. Could the Housing been macined to accept a larger bearing? Looks like we have some major work to do. Thanks for any info. Tom weaver ITA 63

T Weaver 1980 RX-7 ITA

07-09-2002, 12:39 AM
As far as I know it sounds like you had received a newer axel kit not your 80 call complain and tell them to over night. There is a differnce. I`m learning this out. By the way do you refource you shock brackets if not you better mine were 1" from colasping i had them welded but not strong enough I fear what could have happen coming down the hill at Lime Rock it`s nice to have someone lookin out for me
Scott Haven
[email protected]
79 Rx7 ITA/NER

07-09-2002, 12:41 AM
OOps I have it backwards you have a newer housing Good luck Scott.

lee graser
07-09-2002, 11:52 AM
Set the record straight---1980 RX-7's are small axel cars BUT---the disk brake rear(GSL) was was not offered untill 1981. (81-83 GSL = small axels) 84-85 GSL = big axels.

Thus any 1980 car with disk brakes has had a "transplant"---which in this case appears to be an 84-85 large axel (bearing) unit.

07-10-2002, 08:06 AM
Tom, just a bit to the info by Lee. Measure the outside diameter of the hub that is just behind the axel flange that the calipers bolt to. If it measures approx 3 1/4 inch diameter it is the Large bearing rearend. The rearend with small axels measures something smaller. Don't remember the number.

Have Fun

David Dewhurst
CenDiv Milwaukee Region Spec-7 #14

07-10-2002, 03:45 PM
Yes I guess we have the 84-85 Diff, When we bought the car it was supposed to be a "small Axle" So assumeing that was correct we bought a complete 81 LSD thought we would change the center section. HA 84/85 rear. seems like I saw that we could use the 81 rear but would need a different drive shaft? I did locate a complete 84/85 LSD So I need to decide if that might be just as easy to do swap. We have to replace the current center section as it was a"welded" rear and had twisted the axle splines. Anyhow that where we are at on this yet another ITA adventure. Thats for the info and any additional is appreciated. Tom weaver ITA 63 Sayre PA

lee graser
07-11-2002, 10:45 AM
Your 1981 LSD can be used with the late model (84-85) drive shaft---just change out the flanges on the front of the diff-----removal of the big nut with an air power wrench is very easy BUT DO NOT INSTALL WITH an Air wrench----torque by hand to required spec---about 100 + lbs if I recall---better check the book on this. I have done this many times (w/o replacing the crush tube on the pinion shaft ) and never a problem.

Regarding your "twisted" end on the axel shaft----in 10 yrs of 1st gen racing we found this just one time ---suspected that it might be associated with swapping R and L axels (inadvertentdly)--they are physically interchangable-----we started to label used axels (R or L) when removed from street cars and have not experienced the spline twist since ---a fix?? or just luck ?? ---anybody else have experience with this. The theory is that a street axel gets a torque memory in the forward direction for MANY MANY street miles---if the direction of twist(torque) is reversed (R-L axel swap) the axel splines will see a reversed torque and tend to "relax" and the twist that you observed occurs ??