Early type vaccum/ps pump leak???

[dshockley]

I have an early 1991 power steering pump and it has been leaking ever since I got the truck. The previous owner had replaced the gasket between the gear housing and pump three times(2 under waranty), I started there. It still leaks. I think that it is leaking at one of the other gasket surfaces, but am having trouble identifing the location. Does anyone have any experience fixing these assemblies? Can I pickup parts anywhere? I know that there is a common fix for the later pumps involving an odd size seal and o-ring, but CRFF said that my pump was an earlier version. Can anyone help? It is the only leak on this truck!



Thanks

Dan

 

[bgilbert]

When I bought my 89 recently engine was clean and dry only oil was from one of the two vacuum pumps. It was leakin like crazy. He had the mopar vacuum pump in box said it was $350. Took truck and pump to dealer for a few odds and ends, they replaced the gasket u mentioned and installed my new vac pump. No more leakn, feels like more peddle power or less brake effort for stoppn. Your problem might be in the vacuum pump. Whether or not it can be fixed w/o replacing someone else will have to help w/that.

 

[BushWakr - RIP]

I don't want to regale you with old war stories but my younger brother went thur 9, yup, 9, ps pumps until he changed the vaccum pump. No more leaks. The vaccum pump, if damaged or failing will cause "progressive damage" to the ps pump.

In his case he could not go longer than about 4 weeks before the new ps pump gave up.

The dealer had thoroughly checked the vaccum pump tolerances and said nothing was wrong with it..... uhuhhhh... . anyway make sure you are not putting a new seal/gasket/o-ring into something that is just going to continue to make trouble for you.

Vaccum pumps are not cheap either. .



Good luck with your fix...



Bob.

 

[dshockley]

BushWakr,



Was that the later version pump or not? I have heard of that problem with the later version, but hadn't heard anything on the early version.



bgilbert,



Do you remember where the pump was leaking? That is my biggest problem. Because things are so tight around that pump, I can't figure out where it is leaking. If you remembered where yours was leaking, that may help me determine if it is the pump or the gasket.



Thanks

Dan

 

[cfarrar]

I will throw some information about my experience. It may or may not help you. I have an early '91 that had a leaky power steering pump. I took the vacuum pump and power steering pump off as a unit and followed my factory manual's directions for separating them. The power steering pump shaft pokes into the vacuum pump housing where an eccentric with a ball bearing on its outside contacts two steel dowel pins that operate the vacuum pumps. A gear next to the eccentric drives everything. I think that engine oil from the timing case gets into the cavity of the vacuum pump and lubricates the bearing on the eccentric and the two dowel pin plungers that slide in bronze bushings. Leaks in this area would seem to be contained by the pump mounting gasket and o-ring seals around the dowel pin plungers where they exit their bushings. Some oil would probably seep along the dowel pins as they slide. It would find its way into the two pump diaphragms, I guess. My leak was power steering fluid getting around the power steering pump shaft seal that was brittle, but this type of leak drains power steering fluid from the pump into the vacuum pump housing and then into the timing case. I installed a $12 power steering pump kit and replaced the o-rings at the various joints of the vacuum pump and put a new vacuum pump mounting gasket on. My problem went away for the most part. I think that I have some seepage from my vacuum pumps, but it is not bad. I hope that this helps.



Clark

 

[dshockley]

Thanks for the reply!



You mentioned, "I installed a $12 power steering pump kit and replaced the o-rings at the various joints of the vacuum pump and put a new vacuum pump mounting gasket on. "



Where did you get this kit and these o-rings? Stealer? Cummins? Parts store? Thanks for the info. This is what I will do next.



Dan

 

[cfarrar]

Dan, I got my power steering pump kit from Autozone. I know that they are a discount seller, but I was pleased with the quality of the kit. I think that I did come across a name-brand kit on www.carparts.com, (maybe Gates) but it would have taken a while to get. I think that it includes all rubber parts needed for your pump as well as a big bushing for the shaft. I didn't use it because my old one fit close. What I needed most from the kit was the shaft seal. It did not include an o-ring for the high-pressure hose fitting. I went to my hardware store and matched it with one from their assortment of o-rings.



I replaced the o-rings in my vacuum pump assembly with o-rings from the hardware store assortment also. Some or all of them are available from Cummins and possibly Dodge, but I wasn't willing to wait for them to order them and I found everything except the vacuum-pump-to-timing-case gasket that I needed in my small, local hardware store. I got that gasket from Cummins.



You'll need a 14mm metric bolt maybe 1/1/2" long (you are looking for a good amount of thread, not bolt length - grade not important) and a 5/16" or 8mm steel dowel 2" long to separate the gear and eccentric from the power steering pump shaft. I think that it was the coarse pitch variety for that diameter. A metric bolt that large is not found just anywhere. I got mine from a truck maintenance business. It would also be available from a good hardware store or good auto parts store. You'll also need a 3/8" heat-treated bolt (coarse thread, I think) to suck the parts back together. The book says to use a grade 8. Don't skimp on this or you may be drilling a broken bolt out of the end of the pump shaft. I know from experience. Be careful to assemble the power steering pump moving parts correctly. The instructions that came with the kit were helpful.



I hope that this solves your problem, Dan. Like I said before, my problem was mainly a power steering pump shaft seal leak. Sometimes the frothy fluid would be forced out of the filler cap, but the real problem was the shaft seal. Let us know how you get along!



Clark