DaveW

iTrader: (1)

Scottrik

iTrader: (261)

BE VERY CAREFUL--the HD one-way (same as the Yokomo HD one-way) use an oddball metric bearing that is VERY CLOSE dimensionally to the standard TC3/4 diff outdrive bearings. IT IS NOT THE SAME!! I bought two used cars some time back that came with HD one-ways, and BOTH had "standard bearings" that had somehow been pressed onto the HD one-ways. They last a while (one lasted a few races, one lasted a couple heats), but they are tight enough that they compress the one-way bearing(s) and cause them to fail.

The correct bearing for the HD's is easy to identify as it has a "satin" finish on the outer diameter of the shell. The "standard" bearing has a bright chrome finish there.

The correct bearing will barely slide on using only your fingers. The "standard" bearing must be pressed on with tools and substantial force.

I'm not home right now or I'd give you the part number for the HD bearings. They are not available via Boca, Acer, etc.

hth,

Scottrik

ford_racing

iTrader: (6)

They are a metric bearing, they are the same as a yokomo diff bearing ( I have tried this) with a small ring around the outside

Part number is 1731 SP BEARING FOR HD ONE-WAY

mrjake

Thanks Ben and Scottrik for the replys. The Yokomo diff uses a 10x15mm bearing. Have either of you tried those bearings in the TC4 or TC3 diff using the one way? I want to run this car New Years Day, but no one in a 100 mile radius of me has the 1731 bearings. I have them on order, but with the holiday it will be next weekend before I get them.
Thanks,
Bob

DRAG_ON

has anyone try using yokomo solid axle (spool)??? will yokomo spool fit directly to FTTC4? i try to order associated tc4 spool but it always OUT of Stock.

RCpurplecow

iTrader: (1)

So even if I hit the wall a couple of times, the plastic outdrives won't shred with the composite cvd's?

ford_racing

iTrader: (6)

If you were able to get some 0.40" spacers and place it around the outside of the bearing it would work, otherwise you would damage something as the bearing outside diameter is just a fraction too small.

DaveW

iTrader: (1)

Well, hitting the wall can break pretty much anything. There have been a few times i have been shoved into the wall and if i stayed in the throttle when i hit the wall then a CVD will pop out and then eat up the plastic CVD as it spins to a stop. The steel diffs wont let the CVD pop out, if they are going to break it will be when they are in the steel outdrives/spool/oneway... unless you just go headon into the wall, which as said earlier can pretty much break/bend any part. I have heard of guys having the plastic outdrives break, CVDs break etc... i guess its unfair to say they last that long, unless you add to it that you dont hit alot of stuff. If you hit the wall quite a few times a day at the track, and you hit it hard, then staying with the steel diffs and the aluminum CVDs are going to be your best bet.


Has anyone found an answer about the one-way bearings? The part as listed mentions them as a standard bearing, but they arent... as mentioned. I still had my info sheet that came with my one-way when i bought it years ago... it doesnt mention ANYTHING about a replacement part # for the two bearings. Did they just expect us to buy a complete one-way if we needed those bearings... or is it a misprint of the size on AE's part?

LaxRacer

Well ... I have a Yoko one-way, thats brand new. I have an IRS spool, and of course I have the A/E Standard ball diff.

Let me try and do a test fit, I will let everyone know.

C

OK the skinney
I can't find my digital calipers, so i had to do it by eye and with my analog ones.

Here it is,
For clearification, I will be refering to the one way bearing as the bearing in question, and I will try and identify the actual one-way bearing inside the diff as that. Hope that helps.

Outside diameters, practically identical.
Thickness of bearing, the One way bearing is slightly smaller, mayber a hair or so.
Inside diameter, this is the interesting part. The standard bearing is significantly narrower, so much so it will fit the out drive of the oneway, but not the flange of the actual one-way bearing (diff).
Now the one way bearing has a larger openning larger so that it can clear the one-way (diff) bearing's flange, will fit a standard diff / spool, but has way too much play to actually replace the standard diff. I would say the difference could be as much as an 1/16th or 1/32 (over estimated oops) of an inch.

So I suspect that replacement bearing is so that it will clear the one-way(diff) bearing flange. Thats why they have different numbers, and different sizes.

I hope thats clear. Kind of confusing.

C

Matt Dall

Yes this is confusing when trying to source replacement bearings.
Here is the cause of the problem;
AE use Imperial sized screws and bearings, however the best 1 way bearings are German made and metric. To overcome this AE uses a finley machined 15.85mm x 15mm aluminium sleeve which is pressed onto the outside of the metric bearing to adapt back to the 5/8" dimension. Neat and simple solution.
It's quite difficult to spot if you dont look closely.

The actual physical dimensions for the bearings required are;
Standard AE Ball Diff (plastic or steel) needs;
3/8" ID (9.52mm) x 5/8" OD (15.85mm) x 5/32" width (3.96mm).

One-Way AE Diff needs;
10mm ID x 15mm OD, 4mm width.
Also needed is the fine sleeve to take the 15mm back to 5/8" (15.85).
This sleeve can be carefully removed from the old bearings and re-installed to the new ones.

AE sells the "special bearings" with the "special sleeve" pre-fitted to the standard metric bearings.

Hope this helps.

Regards,

DaveW

iTrader: (1)

Funny thing is mine have no special sleeve... inner OR outer race. They are metric inner race and imperial outer race OD. They fit perfectly. Has the sleeve deal been a new addition??

LaxRacer

What he said

Matt Dall

Not sure if the sleeve is new or old? My diff in the TC3 was the same (years ago), as is my TC4. Have also seen it on NTC3 diffs aswell.
I have never seen the 10mm ID and 5/8" OD on the one bearing before? This may be new? Got a picture? I'll make one of the sleeved version.

Regards,

Matt Dall

Here is the picture of the 10mm x 15mm x 4mm wide bearing with the 15.85mm (5/8") sleeve fitted.
This is as it came out of the AE one way packet.

All the TC3 / NTC3 / TC4 One-ways I have ever seen have been like this???

Is there a new version?

Regards,

mrjake

Thanks for the info Matt. My problem has been finding the 1731 bearing so I could get some measurements. None of my LHSs stock the bearing. Associated has made it more difficult by incorrectly listing the size of the bearing in their description.

Thanks to everyone who replied,
Bob J