Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: lizardland on September 27, 2006, 10:43:48 PM

Title: Water pump saga continues...
Post by: lizardland on September 27, 2006, 10:43:48 PM
Anyone know what thread the studs on the pump wheel are (98 4.0L)? I'm guessing 1/4", the four studs on my old pump are stuck solid. Can I just cut down some threaded rod or do I need stock parts?

Cheers,

Stuart
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Post by: tim_aka_tim on September 27, 2006, 11:14:15 PM
Is this the pulley wheel that bolts onto the pump and has the belt runing around it? On an XJ, it just uses 4 bolts. Sounds odd to remove studs then put nuts on the studs when a bolt will do..... or am I not understanding?
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Post by: lizardland on September 27, 2006, 11:39:30 PM
It's the wheel on the pump itself. On the old one it has 4 studs screwed into threaded holes on the wheel, the pulley goes on top of this and the fan is outside and holds everything in place with nuts. The new pump has 4 threaded holes but no studs or bolts. On the old one, the studs just look like pieces of cut down threaded rod with the ends rounded over. I guess there is no reason why I couldn't use 4 bolts, if I knew the thread then I could get a better fit. In fact, thinking about it, it's probably a much more secure fixing.

It totally screwed me up tonight so I guess I'm back on the bus tomorrow :(

Cheers,

Stuart
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Post by: tim_aka_tim on September 27, 2006, 11:49:03 PM
I see, on the XJ, the fan has its own pulley wheel, meaning that the water pump pulley just drives the water pump.

I'd try an M6 thread if it looks like 1/4". I guess maybe Mike would know for sure.
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Post by: Anonymous on September 28, 2006, 10:01:56 AM
sounds like you are confusing the fan pulley with the pump pulley to me......fan pulley has 4 studs, pump pulley has 4 bolts
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Post by: tim_aka_tim on September 28, 2006, 11:18:38 AM
Quote from: "The Kitchen Devil"
sounds like you are confusing the fan pulley with the pump pulley to me......fan pulley has 4 studs, pump pulley has 4 bolts


Agreed - for an XJ, but sounds like on a ZJ, the fan bolts onto the water pump.
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Post by: Woody on September 30, 2006, 11:19:42 PM
Having just had to change the water pump on the XJ today :cry:  On the '95 the fan is bolted onto the water pump.  It uses studs, the problem with using threaded bar is if the nut you are using is stiff you could wind the bar in or out and cause clearance problems.

Woody
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Post by: Tank on September 30, 2006, 11:27:04 PM
On earlier Xj`s the fan bolts onto the pulley,but the 4 bolts/studs are of differing threads.I know this as i just used them to fit a TJ fan to a CJ.They are split 50/50 with a bolt and a nut but one side is a courser thread,one side threading into pully and the nut securing the fan.Might be best to use 4 bolts of correct thread pattern instead if fixing direct to pulley.
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Post by: Woody on October 01, 2006, 01:07:36 PM
Ignore my comment on which pulley the fan sits on my Brain was having a night off :oops:   The fan is on an idler pulley.  My comments about replacing studs with a threaded rod remain though.

Woody