Cal II Auto fluid flow question

[brider]

Some of you may recall my sporadic questions about my Cal II Auto woes. When last we left this subject, I was convinced that the internal O-rings in my tranny input were allowing fluid pressure to leak past and drain the TC at low-flow periods (long idling at stop lights), but at high-flow periods (highway speed) would retain enough pressure to keep the TC somewhat filled (high-speeds still had a LOT of slippage).

So it was suggested that I first look into the ATF tank with the engine running and the wheel spinning, up on the ctr stand, to VERIFY that fluid was cycling thru the tank, which I suppose would verify that the ATF pump itself in the timing case was still working.

Here's what I saw: A layer of foaminess on the top of the fluid level, with a definite slow migration of foam from front-to-back as I looked down into the tank opening. Rear wheel was spinning impressively, and after several minutes of running, the rear wheel seemed to have PLENTY of HP behind it. I could stop the wheel with the brake without the revs climbing (as happens when the TC slips), then overpower the brake with the throttle, indicating that the TC was getting full flow. I am not fooled now, however; it didn't fix itself. I was tempted to drive it to work this morning, but have learned....

So what I think I'm seeing is a return flow of fluid from the cooler, which either has air in it, or entrains air as it dumps into the ATF tank above the fluid level. Since this happens at the front of the tank, it will naturally flow to the rear, as I'm seeing.

What I can't see is if the flow is coming from the bottom banjo fitting on the TC case, which is where my theoretical O-ring blow-by would come from.

I believe what I'm seeing in the ATF tank while running is normal. Can anyone with a Convert or Cal II Auto verify this? Anyone care to comment?

[twhitaker]

A couple months ago Rodekyll was having problems which turned out to be the shaft seal on the pump which would allow the suction side to draw in air, the primary ingredient of foam.

[brider]

Did I replace the seal when I replaced the hex-drive about a year ago???!!! Can't remember.....but I DO remember looking at the seal very closely, looked good....I didn't know pressure differentials were that high across the pump, Rodekyll must've had a really bad seal. I suppose the first thing to do would be to (again) pull the timing cover and replace the seal.

Still, I'd love to hear what someone else sees when looking in their ATF tank with the wheel spinning.

[twhitaker]

I had a Vert with DB bags and a Pacifico Aero frame mounted fairing.

I believe RKs situation was worsened by extra suction requirements. He replaced the seal and the problem went away.

When you think about it is there anywhere else that air can get IN to the system?

[brider]

I had a Vert with DB bags and a Pacifico Aero frame mounted fairing.

I believe RKs situation was worsened by extra suction requirements. He replaced the seal and the problem went away.

When you think about it is there anywhere else that air can get IN to the system?

Extra suction req'mnts? What were those? I'll try to contact RK off-line.

I sold a 'vert with DB's and a Pacifico fairing when I bought my Cal II Auto. It wasn't black, was it?

[rodekyll]

My suction properties might have changed when I put a full sized radiator at about the rear wheel position of a regular Convert.  There is a bit more hose on the suction side now.

My air suck was not at the shaft seal, it was at the pump body o-ring -- the big one that goes around the pump body.  That doesn't mean your shaft seal isn't also leaky.  Since this leak sucks but doesn't blow, you won't see any tell-tale ATF.

The foam is not normal.  It can be in the tank for a couple of reasons -- one is that the fluid level is too high and the returning fluid is colliding with the stuff in the tank, 'whipping a froth'.  Both of the upper hoses on the tank are returns -- keep your fluid level well below those return ports. The other is that air is being introduced to the fluid somewhere in the atf loop.  This can happen due to a leaky hose, leaky crush washers, or bad seals. 

Cracking the lower banjo nut on the tranny will tell you a lot.  With the engine running (wheel in air), crack the nut.  If it sounds like you opened a soda, appears frothy or like you soaped a leaky inner tube and 'sputters' constantly, there's air in the soup.

A better test is to run a hose from the lower banjo to a clear bottle.  Set up the hose and then start the engine (wheel in air).  If there are bubbles coming out of the hose end resembling Seal Team 6 having a pool party in your torque converter, it's either a banjo crush washer leaking or the pump.  I've had either give the same symptoms. 

Don't forget the crush washers on the top of the pump (top of the timing cover).  That's where I found a leak once -- on the suction side of the pump.

Hope this helps.

[brider]

My air suck was not at the shaft seal, it was at the pump body o-ring -- the big one that goes around the pump body.  That doesn't mean your shaft seal isn't also leaky.  Since this leak sucks but doesn't blow, you won't see any tell-tale ATF.

The foam is not normal.  It can be in the tank for a couple of reasons -- one is that the fluid level is too high and the returning fluid is colliding with the stuff in the tank, 'whipping a froth'.  Both of the upper hoses on the tank are returns -- keep your fluid level well below those return ports. The other is that air is being introduced to the fluid somewhere in the atf loop.  This can happen due to a leaky hose, leaky crush washers, or bad seals. 

Cracking the lower banjo nut on the tranny will tell you a lot.  With the engine running (wheel in air), crack the nut.  If it sounds like you opened a soda, appears frothy or like you soaped a leaky inner tube and 'sputters' constantly, there's air in the soup.

A better test is to run a hose from the lower banjo to a clear bottle.  Set up the hose and then start the engine (wheel in air).  If there are bubbles coming out of the hose end resembling Seal Team 6 having a pool party in your torque converter, it's either a banjo crush washer leaking or the pump.  I've had either give the same symptoms. 

Don't forget the crush washers on the top of the pump (top of the timing cover).  That's where I found a leak once -- on the suction side of the pump.

Hope this helps.

Where might a person buy the pump o-ring and seal? I found the crush washers @ MGCycle......

[rodekyll]

I get mine at Moto International in Seattle.  Other genuine dealers might also still carry Convert stuff, so ask your regular authorized dealer, too.

[brider]

So back to the test procedure:

I'm going to take video of the frothiness in the ATF tank, then the results of the lower banjo evacuating into a container, and try to get them to you or post them for you to evaluate.

Question: With the lower banjo line pumping into a clear vessel, how much time should I have before the ATF tank begins sucking air at the pump intake? Should I start by over-filling the tank? If the system was in 100% condition, should I see a solid flow from the banjo line, with no evidence of air?

[rodekyll]

One of the things I noticed in my tests was that when the pump sucked air it also pressurized the fluid tank.  I had a pressure gauge on mine and got up to 15# of pressure in the tank.  You can check it without a gauge by covering the vent tube with your finger while revving the bike a little for about a minute.  Remove you finger and watch/feel/listen for pressurized air escaping.  If you have trouble detecting it you can put a hose from the vent to the bottle and watch for bubbles or you can hold it near your ear, remove your finger, and listen for the fart.

The amount of time before the tank gets empty will vary according to the amount of fluid in the tank and the ability of the pump to suck.  At idle you'll get at least 30sec.  Don't overfill the tank.  Use a funnel lined with a painter's filter to reuse the atf, at least until you're done troubleshooting.  I used two large, plastic vodka bottles.  I'd swap bottles and recycle fluid without shutting the engine down.  With the clear bottles it was easy to keep an eye on the bubbles and the tank level at the same time.

If you're sucking air the bubbles will be copious and obvious.  It will either be huge scuba bubbles or tiny beer bubbles.  A normal system has zero bubbles.  Read that: none.  No bubbles.

You might also have a herky-jerky, fitful fluid flow that may not start immediately upon engine start, and may stop occasionally even though there is fluid in the tank.  You might get little or no flow at idle.

All this is going to overheat the fluid, so count on changing it after you're done. 

[brider]

You might also have a herky-jerky, fitful fluid flow that may not start immediately upon engine start, and may stop occasionally even though there is fluid in the tank.  You might get little or no flow at idle.

I will assume that inconsistent or no-flow is a sign of a problem.

Thanks for your help, I'll post my observations.