I have a 70 FJ40 with the man-a-free front disc conversion, I believe these would be course splined axles? Will the birfields from a 75 FJ40 on up swap out with my birfields? These would be fine splined, right? I am looking for a spare set of birfields for my cruiser in case of breakage. I also want to cryogenically treat the birfields so they will not snap. I have a buddy that has the cold fire system and he treats ford escourt engine parts that are running 500hp with nitrous and no breaky yet! <IMG SRC="smilies/redface.gif" border="0">

nope the course birfs use a different spindle that the fine spline outer shaft wont fit through. and you cant bolt up the bigger spindles. I forget why. bolt pattern maybe?

Yes the '70 front end has course splined birfields. The ones from the '75 are also course splined, and will work, since the disc brake front end (and fine splined birfields) came in '76. If you end up swaping out your birfields, you also need the fine splined hubs, spindles, and knuckle housings.

One good thing about your setup is that the course splined birfields and hubs are cheaper than the fine splined parts. Plus the birfields almost never fail in the splines - usually it's the inner or outer cage that goes (BTDT).

Hope this helps.

[ 09-11-2001: Message edited by: FJ4ZROX ]

I was thinking disks came out in 75 for some reason

Originally posted by 1970cruiser:
<STRONG>I also want to cryogenically treat the birfields so they will not snap. I have a buddy that has the cold fire system and he treats ford escourt engine parts that are running 500hp with nitrous and no breaky yet! <IMG SRC="smilies/redface.gif" border="0"></STRONG>

Tell me more, and how this would really work over the way axle shafts are already hardend.

On the birf situation i would covert to toy disks so that you can run the bigger birf. They are much stronger, but still incredibaly weak. You would mostl likely make money in the conversion too, by selling the man-a-free stuff.

Originally posted by FJ4ZROX:
<STRONG>
One good thing about your setup is that the course splined birfields and hubs are cheaper than the fine splined parts. Plus the birfields almost never fail in the splines - usually it's the inner or outer cage that goes (BTDT).

[ 09-11-2001: Message edited by: FJ4ZROX ]</STRONG>

The course stuff is cheaper but the cage and shell are smaller and weaker that the fine birfs, and when i had drums i broke 2 of the stubs right at the splines and 2 at the outer cage.

[ 09-11-2001: Message edited by: COMPLAINE ]

I don't think you can really make a birfield really strong. The real solution would be to run a D60 front axle. Just treat it with respect and know what not to do (back up while turning) and it should last a while.

Charles

buy newfields and convert to truck disks

Save your $500 on the Newfields....that is 10 spare Mini Birfields and that is a better buy....trust me been there done that.

OK I do not know how to pull down a line of text from someones response but for the "Tell me more" here it is. All important parts are case hardened, that means heat treated, cryogenically treating takes the part puts it in a chamber and takes it down to -400degrees then brings it up to +300. It them takes it back down again and so fourth. Go to www.coldfire.com, (http://www.coldfire.com,) I think, and it will explain more. Alot of guys with Ferrari's get there brake rotors treated and they last 10 times longer. People treat their golf clubs and bats too, my buddy plays golf and his golf pro hit a ball with one of his treated clubs and it went the furthest he had ever hit a ball before. It has to do with lining up the particles in the metal, all I know is there is a guy with a civic that had his engine done by my buddys shop, he is running 300hp with turbos, and has a 300 shot of nitrous, he has had this engine for a year and dogs the hell out of it, no carnage! Do a search on a search engine for cold fire and read the article...amazing! Mayby a cheap alternative to axle swaps and a birfield solution....... <IMG SRC="smilies/eek.gif" border="0">

George at Newfield (CV Unlimited) claims his 4th generation Newfields are Heat Treated.

They looked different than the first (and second) batch I tested.

Birfields are just not designed to do to them what we do to them.

I've snapped 2 2nd gen Newfields and Reuben has snapped 2 3rd gen Newfields.

I've got the newest 4th gen's in there now...and so far, with 2 very difficult trips and doing some things that I KNOW would have snapped minitruck birfs, they've held up.

Time shall tell....

I've got a 4th generation Newfield. What is the purpose of polishing them. It is nice and looks very shiny. Not sure about the strengh. I don't think any level of heat or cold treating will make a birfield as strong as a D60.,

you cant bolt up the bigger spindles. I forget why. bolt pattern maybe?
You cant use them because the drum wheel bearings are smaller due to the smaller spindle