What is the thread on the water pump of a Saab 99? Old style, and/or new style. I know it's left handed and metric, but before I order a tap and die set for it, I'm hoping someone here can tell me definitively.
I have borrowed a water pump removal/insertion tool from our local independant guy, and his is chewed up to the point of almost unusuable. If I can make some new parts for it for him, that'll work better for me, and will give him incentive to loan me tools again if I need something.
Anyway, 12mm left hand, maybe, for the new, and 6mm left hand for the old style is my guess, but I'd love to get a confirmation. I don't have thread gages for metric...
Hi Dave, I'm sorry I cannot go out and measure for you.... tools are far away, and I dont have a pump-shaft outside of an engine to measure. From memory then, that is all can do: My 1980 99 pumpshaft thread was left handed, metric, definately NOT 6 mm. AND definately NOT 12 mm. I think it was 8 mm, as the wrench I used was 12 or 13 mm. If the diameter of the shaft is 8 mm, then the thread is most likely 1.25 mm. (8x1.25)
I made a tool from a thing they use for tightening steel cables, I am sure you know it. These consist of two threaded pieces with hooks, one left handed thread, one right handed thread. They are connected by a sort of tube with left handed thread on one end, and right handed thread in the other end. You tighten the cable by turning the middle part..... what is that called in English?
I've got one, but it's at home and I'm not, and I was hoping someone would have it.
Ah, OK. I need to get the cover off and measure it; I was going by visual memory of a 10-year old event, which apparently distorts things a bit.
So at that diameter, the standard pitch is 1.25 then? How big of a shaft before the normal thread pitch goes to 1.5mm, do you know?
Ah, a "turnbuckle" they call it here. They sell cheap aluminum ones here, and it's at least possible that they're imported and metric thread. Thanks for the thought.
Yes, I remember those holes! I figure they let trapped air escape after filling up with coolant. One hole would cause imbalance... so there's two. (Just my guess .. :)
I have thought really hard for a reason the thread on the shaft is left... its the only left-threaded thing in the car....
If you lift the shaft, it MUST turn a bit to get out of the gears in the engine that drive it. If you just lift the shaft, and not rotate at the same time it will never come out (and something will break.....! Gears maybe even.... ;) The shaft needs to turn counter-clockwise if I remember correctly.... and if they had used a right-thread then all you would achieve is unscrewing the tool from the shaft and pushing the shaft back into the engine.
Pfew... kind of hard to explain.... but obvious when you have a good look at it.
Just got my spare brand new 99 water-pump out. part 8358491 with 12 cogs, as opposed to the 8 cog variety, depending on your auxilliary shaft cog number. It has a 12mm x 1.5 thread.
Thanks, Richard. I ended up spending some quality time in my basement/ machine shop this weekend. I've got a Rockwell lathe, with the metric threading gears as an (unused) accessory. They were still in the original box from, probably, the 1970's.
The water pump tool had the 12mm x 1.5 LH thread you mention, like the
12-cog water pump shafts. The balance shaft (layshaft?) in the B engine that I put together had 8 cogs, because it's apparently from an older
No matter (I have the right distributor gear also).
So...the broken water pump shaft (teeth gone, corresponding with the teeth gone on the layshaft of the engine it had been in, the KaBoom engine), went into the lathe, cut off, turned down to the proper diameter, and I setup the lathe & cut the appropriate threads onto the other end of it. So, I now have a double-ended stud, the bottom of which screws into the top of an 8-cog water pump shaft, to make the top of it look like a 12-cog waterpump shaft, so the tool works. Possibly the only one in the state of Wisconsin, at least. The pump pulled right out, the new one went in very well with the right tools, and it holds water now which is sort of a main feature of a water pump. Got some gasket material today, will put it all back together hopefully tonight and start it up.
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