Help, my rear is too wide, I think

[seadevil]

I need help identifying the rear I bought for my Mk IV. The unit was included as a package deal when I found a Tremec 3550 for sale. The seller threw in the rear and an old 5.0 for a few extra bucks. Now I need to figure out what I have before I buy the five lug axles. There is no tag on the assembly but the casting has the following identification (E5SW BA4). I have found statements claiming this came from an ’86 Thunderbird. I don’t know if that’s correct or not, but I don’t think the pedigree is important so long as the dimensions are good. So my next problem is that I don’t know where to measure from. The pic in the attached file (E5SW BA4.jpg) has three references. When I measure from “A” the axle is 60 1/8”, from “B” it is 59”, and from “C” it is 55 7/8”.

The tech folks at Factory Five told me and 87-93 axle would be 59 ¼” and a 94-98 axle would be 61 1/8”. They told me the wider axle will probably cause my tires to rub when pushed (I bought the 10 ½ by 17” rims and plan on 315 tires). One added note, the existing axles seem to have a good deal of end play, possibly 1/8”. You can add that tolerance +/- to my dimensions above.

[Jeff Kleiner]

The 59 1/4" dimension would be flange to flange, what you have labeled as "B", so it looks like you have the proper '87-'93 Fox width.

Jeff

[rich grsc]

Your measurements really dont mean anything as you are going to replace the axles anyway. You need 5 lug axles, so you will buy Fox length axle.

[seadevil]

Jeff,

Thanks for the clarification.

[seadevil]

Rich,
There are different length axles you can purchase for the 8.8 rear assembly. Are you saying that they will all fit and that they just stick out further? I thought that the rear assembly was produced in different widths and the axle lengths needed to match those assemblies. If, for example, my assembly was wider, the shorter axles would not insert far enough to allow for the C-clips to fit up.

[GT-Tom]

Rich,
There are different length axles you can purchase for the 8.8 rear assembly. Are you saying that they will all fit and that they just stick out further? I thought that the rear assembly was produced in different widths and the axle lengths needed to match those assemblies. If, for example, my assembly was wider, the shorter axles would not insert far enough to allow for the C-clips to fit up.
seadevil I believe you are correct. I purchased a later model (but new) Ford 8.8 rear and had to shorten the axle tubes to accept the fox width 5 lug axles. Here is a link to the other forum with some info on axle widths.

http://www.ffcars.com/forums/17-factory-five-roadsters/286767-rear-axle-question.html

Tom

[seadevil]

Thanks Tom,
Your link was a great help. I am beginning to grow some confidence that i have a Fox length assembly, but i don't have any inclination to shorten the tubes if i purchase axles that end up too short. My next plan is to talk with Ford Racing tech line on Monday to see if they can cross reference the casting number i found (E5SW BA4), and also to call Richard at North Race Cars to discuss my measurements.

[montyals]

So are you guys saying...for example...that a rear end from a 99 Mustang GT...I think it's 62" doesn't matter as long as the axles are replaced with shorter axles that don't stick out as far?

[Jeff Kleiner]

So are you guys saying...for example...that a rear end from a 99 Mustang GT...I think it's 62" doesn't matter as long as the axles are replaced with shorter axles that don't stick out as far?

No. The axle housings of '94-'98 are the same width as the '93 and earlier Fox cars but the axle shafts are longer with all of the extra width outside of the housing. They can be brought to Fox width with shorter axles but no change to the housing. '99 and later housings are wider and can not get to the Fox width without being cut and narrowed.

Jeff

[montyals]

Thanks for the explanation. You just save me some money...and time!