keep losing the tail shaft seal in falcon

[rubbinsracin]

we have lost 3 tailshaft seals in our falcon transmission this year. (2 races and 1 play day) not a big deal as not a ton of fluid is lost, but its enough to coat the bottom of the car making everything a freaking mess to work on and we can never get it clean.

only think we have changed from last year to this year was put a new fast shaft driveshaft(2" shorter) on to replace the old beat to crap heavy one we had with a new 8" yoke to replace the old 4" one we had. we have about 4" of the yoke sticking out of the drive shaft and the rest inside. do we need a longer drive shaft to keep more of the yoke inside the tailshaft?

[mudderfudder]

make sure that your bearing at the end of the tail stock is in good shape. with the driveshaft in place, try to wiggle the yoke up and down. if there is alot of play then i would replace it. very simple job, i think 6 or 7 bolts, take seal out, make sure that you get retainer clip out then what i use is a socket with enough extention added to tap the old bearing out. if that isnt the problem then make sure your yoke doesnt have any burs and clean up any rust or grime that might have built up on it. hope this helps.

[andy16]

i am having the same problem... will check that out

[FlatTire]

I have run a falcon for years and never had a problem. I also run the extra long 8" yoke. You need to keep enough yoke in the housing so the end of the yoke is ahead of the
tailshaft bearing when the LR is hiked up and the RR is compressed. I suspect since you went with a shorter shaft that the yoke is close to sliding out of the bearing causing a misalignment wiping out the sealing and maybe causing
some harm to the bearing.

Heres what you need to do:

Take the springs off the rear end. Let the LR drop all the way. Compress the RR to its maximum travel. See how much shaft you have inside the transmission. I'd try for 3" or so.

Now Put the springs back on and set the car on the floor. Measure the distance between the end of the tailshaft and the start of the chamfer on the yoke. You want about 2" of yoke
exposed.

My tailshaft seal seats very tight into my housing. The only reason you would need to add screws like a Brinn is if the interference fit isn't adequate.

[rubbinsracin]

So with the 8" yoke you have 6" or so inside the housing with no problems at all?

[FlatTire]

Yes sir. All of this can be figured out by taking the springs out and articulating your rear suspension while the car is on the jack stands. Move the rearend thru its travel simulating what happens
on the track. All rearends will articulate differently depending on bar lengths and angles so yours might be a little different.

[powerslide]

you should check for a crack in the tailshaft. My buddy had one that was cracked and wouldnt hold the seal tight enough. He used a hose clamp around the tailshaft and just a couple L pieces of metal to hold the seal in. Just dont get them too long.