Two Quick Questions

[grimlock97]

1978 SII, 345, Pertronix Ignition, I just finished rebuilding the top end and cranked it up a few times in the past couple of days, I went to back it out and it backed up fine, but my clutch was completely gone, it worked fine 3 weeks ago when i started the rebuild, (here's the thread on the rebuild http://www.ihonlynorth.com/forums/ga...pushrods.html), now it goes to the floor with no resistance, i can still shift when the truck is off, The other issue that has risen is my power steering pump pulley flew off after a couple of minutes of running, i pressed it on with a tool, bleed the system and it worked fine when testing the motor, as soon as i tried to turn, it went flying any ideas?

[RobertC]

You need to post a picture of your p/s pump. I think there were at least 2 used on the Scout II over the years.

I think on an "older one", the pulley is held on by a nut / lock washer / washer... (memory???)

On the clutch -- is it always engaged? Did you knock the return spring off / not replace it while doing the other work?

[Robert Kenney]

Grimlock,
Went back to look at your pictures in the pushrod post and they are not there. I wanted to see the PS pump.

Some do just push on but the interference fit is critical. On a
.750 diameter shaft a minimum of .001 and a max of .0015 between the shaft and the bore will be required to hold them tightly together if a cold press fit is used. Shaft .7500 and bore .7490 -.7485. More interference than that and you will need to heat the bore about 450-500F and push it on hot. After it cooled it will be on for good.

Also the bore needs to be perfectly straight and parallel. If you have taper it can wobble on the shaft loosening over time.

A micrometer and bore gauges are going to be required to measure the interface along with proficiency to use the tools correctly.

[grimlock97]

Pictures attached, the pump i pulled off was a press on pulley, the new pump is a press on pulley, there is no not to hold it on, the pulley it's self is the one that came with the scout.

[grimlock97]

Thanks, i will have to get a micrometer and bore gauge to measure, it was really tight pressing the pulley back on, i was very surprised that it came flying off like it did.

[grimlock97]

I'm sure this is a bad idea, but i just wanted to know if it would hurt if i just welded the pulley on since it doesn't seem to want to stay on by itself?

[Robert Kenney]

Mechanicaly it should be ok but the welding heat can destroy the shaft seal.

[grimlock97]

Originally Posted by Robert Kenney

Mechanicaly it should be ok but the welding heat can destroy the shaft seal.

So to be safe i can just do short welding bursts with my mig after pressing the pulley on, and just take it in about 4 main places?

[Robert Kenney]

Just allow the assy to cool between welds say for 10 minutes.

Personally I would weld completely around. But....... your way
should be OK. Just periodically inspect the welds for fracturing.

Any chance you are building to much system pressure and twisting the pulley off?

[grimlock97]

I welded all the way around, but in short bursts letting the metal cool before continuing, it's not pretty but it's holding, what would cause the pulley to get too much pressure? Also, i think the pulley is just a little too big or the shaft was a little too small b/c i put it on tapping it with a sledge hammer this time and it went on really easily. Thanks for all the help.

[Robert Kenney]

That was a long shot possible cause. If you are seeing no other symptom that is not likely an issue.

The PS gear valving should be open center and fluid should flow with little or no back pressure from the pump back to the reservoir when the steering is neutral (no steering wheel input).

As you turn the steering wheel the pressure should rise proportionally with steering input and tire turning resistance.

A gauge can be put in the pressure line if needed.

[grimlock97]

Okay, Thanks, after welding it on, it turned like a dream, i need to bleed the lines a little and top off, but other than that it turned great and didn't wine or grind like it was before, thanks again for the help.