Differential breather tube spitting lube

[chuckcobra]

I'm loosing lube out of the differential breather on my coupe replica. After a 30 mile drive, there is a good size puddle on the ground and the rear of the frame is nicely coated with diff lube.

The diff is a Kirkham unit and it is not overfilled. I'm running the correct diff lube. The unit has about 200 miles on it and does not appear to be running hot or having any mechanical or internal problems.

I've tried several approaches to stop the problem with no success. (1) extended the breather to a high spot (several inches above the top of the differential) with hose and (2) used a cap with two 1/16" dia holes at a 90 degree angle to the tube centerline.

This can't be rocket science and I am hoping that I am just overlooking something obvious.

Any ideas?

Chuck

[Turk]

Contact Kris Kincaid from Shelby for a modified diferential cover, otherwise you will be going through what others have.

Pat Buckley is running 11 feet of tube and a 18" riser and his differential has been spitting out oil ever since.
He has tried everything!

TURK

[mj_duell]

Chuck,
Try this. I had the same problem with my nine inch. I used about three feet of rubber tube that feed into the bottom of a tilton remote brake reservoir. I mounted the reservoir about a foot and a half higher than the rear end on the inside/back of the trunk. Whne the rear end pressurizes , it will push oil up the tube into the reservoir and when the pressure is relieved it will drain back into the rear end. The whole set-up cost about $15.00. The plus is I can add oil to my diff any time I want through the top of the reservoir.



--Mike

[chuckcobra]

Turk and MJ,
Thanks for the reply, but it seems like both responses are treating the symptom without getting to the heart of the problem.

I have two other cobras, both with the Salisbury differential, and neither has this problem and neither has such an elabortate lube control system. Heck, the Jag units are almost identical to the cobra unit and they don't have the lube spitting problem either.

There has got to be a explaination for the root problem. Does anyone on the forum have an old Jag or Cobra rear cover that is off the car that they could measure to see how the vent tube location compares to the Kirkham piece. My thought is that it is conceivable that the Jag / Cobra unit is slightly different than the Kirkham piece (e.g. maybe the vent tube is right in the line of fire).

Guess that maybe I should put in a call to Tom and Dave K.

Chuck

[ENTDOC]

Chuck please keep us updated on your progress as I too have the Kirkham diff and may face the same problem when running.chuck smith

[wilf leek]

Chuck - we were talking about this on Gasholes when Pat Buckley was trying to figure out why his diff pukes oil like yours. I put up a couple of pictures of the inside and out of my Jag diff cover there at http://www.gasholes.com/yabbse/index...1062;start=795 bottom of the page.

One thing was clear from my own diff cover - the Jag breather is baffled, and also well out of the way of oil being flung off the crownwheel.

Apologies to Brent if I am out of line linking to another site! Is that acceptable netiquette?

[chuckcobra]

For those of you following this post, I spent some time discussing the issue with Tom Kirkham. The present thought is that the differential is in fact to full. According to Tom, filling the diff to the bottom of the fill plug is incorrect and results in a level that is to high in the diff housing. Several of their cars have the lube level approximately 1" below the fill plug. He suggested that I refill the unit with the specified volume (the orginal Cobra manual specifies 3 US pints). This should put the lube level at approximately 1" below the filler plug and should solve the problem.

Tomorrow I will drain all the fluid out and refill with the correct volume (not to the filler plug.)

I'll post another update if this turns out to be the solution.

Chuck

[RICK LAKE]

Chuckcobra 2 questions? Who's fluid are you using? Synthetic fluid semi or full? Are you using a climbing fluid the slicks to the gears and bearings? If you are doing some hard driving for along period of time, the heat buildup is causing the problem. 2 ideals, make some small wide scoops under the car to push air onto the center of the carrier and cool it down. Go like nascar and build acooler and pump under the car to cool the rear. You could go electric or run it off the drive shaft yoke. I think thhis will solve your problems. If you get orange ducting like nascar uses, they make little 4" 12 volt fans that will force the air on the rearend and cool it. I think Don C with the periscope to the rear while being great engineering is a little over kill Don system worked great for the rear brakes and rearend of his comp car. Good luck Rick Lake tells what happen after the repairs