water pump drive gear

[applpro]

About 6 months ago I had a problem with my '01 'Shee overheating on occasion. After changing several parts- New Toomey Radiator, Noss Cool Head, changed to Engine Ice- I found the real cause of the problem.

The plastic driven gear on the water pump was stripped out-still would turn sometimes because the plastic was melted to the shaft. I ordered an aluminum impeller from Vito's & replaced the bearing, seal, pin & gear also.

Everything was fine until this past weekend. I was riding it wide open in fifth-just getting ready to hit 6th- when the motor seized.

Upon teardown I discovered lower ring on left side piston seized, upper ring & both rings on right side ok. No problems with jetting- looked to be cooling issue again.

Took the cover off & guess what? Goddamn f???ing gear stripped again!!

Anyone ever had this happen? bearing was not seized, it spins freely. The only thing I can think of is that the impeller seized at the small end where it's supported by the engine case. It appears to get splash oiling from the spinning clutch assembly. Is that right? I'm pissed off right now & my first thoughts are to dump this friggin quad but surely the fix isn't that complicated.

[BdBanshee]

I have a friend that had the same thing happen, only it happened the 2nd day we were at Glamis 1400 plus miles from home!

 

I found that there was too much clearance between the "e" clip and the plastic gear. I guess it was letting the drive pin come out of the drive slot in the gear. I made him a thicker washer out of S.S. and it has run fine since.

 

With new parts assemble it and take a feeler gauge set and see what size feeler gauge will fit between washer and drive gear without being too tight. E-mail me the thickness and I'll make you a thicker S.S. washer to replace the stock washer.

 

[email protected]

[applpro]

I have a friend that had the same thing happen, only it happened the 2nd day we were at Glamis 1400 plus miles from home!

 

I found that there was too much clearance between the "e" clip and the plastic gear. I guess it was letting the drive pin come out of the drive slot in the gear. I made him a thicker washer out of S.S. and it has run fine since.

 

With new parts assemble it and take a feeler gauge set and see what size feeler gauge will fit between washer and drive gear without being too tight. E-mail me the thickness and I'll make you a thicker S.S. washer to replace the stock washer.

 

[email protected]

382233[/snapback]

Makes sense, just never thought to check that. I'll let you know after I get the new parts in. THANKS!!

[markevo6]

I have had exactly the same thing happen to mine as mentioned.

 

Quad was running hot , shooting water out .

 

By the time i worked out the cause it was too late , seized it !

 

Now having a rebore and new pistons etc .- weisco pro lights

 

Thought i'd check the impeller before rebuilding it and same problem - the plastic drive gear had melted and wasnt turning the impeller . I reckon this happened to the previous owner and he seized it , then just chucked it back together and sold it on, rather than rebuilding it and solving the original cause of the problem .

 

Quick question , is there an uprated drive gear you can use or are you stuck

with the plastic one.

 

This would be a good subject to do a write up on and make it a sticky as there seems to be a lot of owners having these problems.

 

Good luck peeps

 

 

Mark

[willaduncan]

Mull engineering makes a billet gear imo its not worth the extra cash to buy tho just throw a light coat of grease on the shaft of the impeller and make sure there is no play in the gear up down or turning on the shaft and your good

[blowit]

We are the manufacturer of the billet drive gear. We designed it due to concerns from our customers and our experiences with customer engines. In testing, we determined that at operating engine temps, the plastic gear can get rather weak and something as simple as a tight bearing can cause excessive torsion and cause it to fail. While the plastic gear has proved to get the job done most of the time, it only takes one failure to cost a guy an engine and when many here are spending thousands on high HP builds, it just puts the mind a little more at ease that though even our billet gear can fail, the seal and bearing are very likely to fail first and give warning for repair before total failure.

 

As well, it is a known problem with many plastics subject to heat and oil submersion. The oil works to break down the chemical bonds in the plastics, making them brittle.

 

All in all, the gear was designed and released as a preventative measure. That being said, we have not had one call of a billet gear ever failing in an engine to date.

 

 

Brandon

Mull Engineering

Edited December 21, 2011 by blowit

[10milmike]

Do u guys have a web site could not find it thanks.

[blowit]

Do u guys have a web site could not find it thanks.

 

 

www.mullengineering.com

 

You can also clink "link" above my signature. Not sure why I cannot make the signature itself hot, never looked into it. Let us know if you have any issues navigating.

[06specialedition]

I've ran a gear from Mull for about 1 year with no issues. Mull's quality is top notch, I've talked to Brandon a few times on the phone and the guy knows his stuff.

 

I've seen too many plastic gears fail to even consider running one.

[007banshee]

Good thing i found this,in th's process of rebuilding my engine just about have the bottom.end done.just have to adjust tranny and seal her up. So you guys suggest a billet impelled and.mulls gear? How much would these run and wheres a good place to get impellers. Sorry for hyjackin this thread btw.