The water pump on our cars is, I believe, five main pieces. The pump housing, the impellar (My last one was nylon/plastic), the bearing, the seal (or seal system), and the shaft.

The shaft is reused, the housing is reused, and the impellar, unless damaged, is reused.

The pump, when worn, will need a seal or a set of seals, and a new bearing.

Why not take a pump, press everything apart, and find the correct seal size, and the correct bearing, and try it out. Yes, there is labor involved, but really - if the bearing that you buy is of a better or same spec as the one that was originally in the unit, then there is no reason for alarm about anything blowing up.

I suppose that I missed one point: The pulley itself. I remember getting a NEW pump when I redid my 89S4, as I wanted something to get me another 50k without any problems. The pulley was shiney. If the pulley is in good shape, why not use it again?

I think of it this way: We will not always have parts available like we do now. Porsche makes less and less parts for our cars every single month. I should probably learn to make maintenance or improvement to my two 928s without NEW parts, as I will not always have them available, but I will always have these cars.

 

I have been lucky with alot of things, but sacrificing your motor over 50 bucks is not worth the risk. I would stick with the big three. I purchased many parts from different places and have a garage full of wrong parts. Whenever I order from the big three, not only do I get quality parts but it's the experience that they have with each model that makes the difference. Sal

 

Reno,

Well Said.

Greg

 

What is a person sacrificing when he or she does the EXACT same thing to an automotive part that a assembly line rebuilder does? These people are not rocket scientists. They are assemblly line rebuilders. They find out how to rebuild a part, and replace "certain" assemblies inside the part.

 

There is that word called "experience". When you have rebuilt a few hundred pumps, you tend to know what to look for as far as potential failing components. I am not sure if I could identify something that may have an impact on my work later on down the road IMHO.
The people that Jim is talking about obviously have lots of experience.
Yeeesh guys, remember that the t-belt / waterpump combo on our cars is friggin' scary stuff if it lets go - interference motors at least...
I definately advocate saving money whenever possible, like that Auto - carbon fiber shift handle that some people carry for like 50+ dollars and I bought the same one at Pepboys for 20.00 but I draw the line at this stuff. Timing belts / waterpumps / tensioner parts, etc will definately come from our BIG3. I just have this scary thought of standing at a customer returns counter with an armful of engine pieces trying tell some 16 year old that the waterpump I bought from them failed and helped blow the hell out of my engine.....hhmmmmm nahh, I'll stick to what I know for sure.

 

I have some basic shop tools, some experience & common sense. In the absence of any housing cracks or other failures, I won't hesitate to rebuild it myself. Part of owning a car such as the 928 has always meant a bit of self-sufficiency (to me, anyway). Saving $100 for an hour of what I consider fun is fine, too...

 

My point is that too many times in these pages and in the 928 email lists do people assume that there is some sort of special black majic.

ONE GUY (although well trained) puts together the AMG engines for the Mercdes Benz super sedans. With a few simple power tools hung from the ceiling, and a few hand held ones, he assembles what is to be regarded as one of the most powerful sedan engines in the world, and from a company built upon the idea that you buy it because you want unflappable quality. He is human just like me. And so is some rebuilder who knows he won't get the bill for when the water pump seizes.

He uses those slightly conical piston ring compressor tubes to insert the ringed pistons into the block. You know, like the one you can get in the summit cataloug. They used to bash them in with thier nuckles, but not they have a simple tool to do the pressing in.

 

Brendan.....and nearly anyone can sell Insurance .....or does knowledge , experience , and training come into play ? If you have never pressed a pulley off of a shaft how tight should it be ? where should it be located ? Do you simply make it like it was and assume that it was correct before ; it should be correct now ? That logic when applied to timing belt tensioning has caused a lot of people a lot of grief . Water pumps are rather simple , yet I have heard where the impeller was not pushed on far enough and when the pump was bolted to the block it could not turn . I have no doubt that you could be trained to be a highly skilled experienced water pump re builder and as such probably would be paid about $8.00 per hour , as you say it is not rocket science unfortunately we even have some issues with rocket scientists .

 

Jim. My good friend Jim.

Anyone can get an insurance licence. Knowledge, experience, honesty, and integrity DO come into play if you succeed enough to have any clients.

IF I can reinterate my points, I think that what I originally said holds true:

Porsche parts are just like all other parts, and it is not witch craft. Many people in this world would like us to believe that it is witchcraft, and you have to do special dances to and salutations or it all blows up (this is separate from the required Timing Belt dance upon full disassembly)

How long do you think that Porsche will make NEW parts for the 928. How many years until the supply of say these rebuildable water pumps, or the TT, steering racks totally runs out? Do we all dump our 928s then? This is the questions upon which I state my claim: We need to be able to do these things on our own so that I can have my 89 or 81 928 in perfect working order when my 5mo. old turns 16 and wants the keys.

Timing belt tensioning is not rocket science. There is a right way and wrong way. One would want to find out the right way.

I am sure there are measurements that these rebuilders use to make DAMN sure that the impeller is pushed on correctly, and atthe correct depth...Where or from whom can I find these measurements Jim? The rebuilder does not do anything hit and miss: He found out how to do it. Why can't I and be ready for the day HE doesn't see a market for rebuilding these WPs?

Don't even get me started on a TT: Two or three 6006 or 6007 bearings, a shaft, and a tube (and a harnmonic balancer)

 

I find myself agreeing with Jim and Brendan.
Brendan - you make good points about what do we do later, etc. I am a full advocate of owners servicing their own cars, I started a site dedicated to that mission. Rennlist is also dedicated to the same mission. Its like the OD gear isn't it? "oh, you need to send that back to a VDO authorized repair station to the tune of 150+ dollars to replace a very simple gear. Believe me, I know exactly where your coming from.
I DO believe, however, that the cost of a professionally remanufactured waterpump doesn't warrant me going after the rebuild myself. There not expensive. I decided to try my hand at rebuilding the airpump and that was a waste of my time. The rotor in the pump was toast and there were parts of the wipers floating around inside. If the wtaerpump cost 500-600 dollars or something I could understand the desire to tackle the rebuild yourself but they're cheap!!!
Like 100+ dollars or something. The T-belt is 50.00 - no big deal.....

Here is my humble opinion - Its your car and you have the right to work on whatever you feel like. I would much rather rebuild the pump myself or have YOU rebuild it than to buy a pump from a NAPA dealer. I would know nothing about that pump. 928Inter. pumps come with a history so I would feel comfortable with that.
Point of fact is ------your both right.

Buy a known pump from a reputable rebuilder that is endorsed by a company that we know and trust OR---tackle the job yourself and see how you feel about the results. My only concern would be not knowing if I did it right in the first place. I don't personally feel like finding that out the hard way. Pumps are too cheap!!!!

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Oh, and if you do rebuild one yourself, please take some pics and write up the procedure for the rest of us to use...........
<img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />

 

Brendan, I'll show you an example. If you are changing your timing belt, Devek says that you must use a Porsche timing belt. And the reason they said this was because use of any other belt other than Porsche resulted in failure. yeah the belts both look the same but it's the quality of the parts that make the difference. I tackle alot of things on my car but some things are better left for the experienced.

 

reno,

Big difference between using the *wrong* part and skillfully renewing a (standard) bearing & seal in a waterpump housing!!!

 

IF they were available I'd try a NAPA waterpump IF it didn't have a metal impeller.I once saw the damage one did to a Porsche block when the bearing let go...NASTY.

 

They may have said that the impeller is metal, but the pump pictured on NAPA's web site has a plastic impeller. As far experience in rebuilding water pumps, how many rebuilt water pumps do you think NAPA has sold over the years? How many water pumps do you think the rebuilder that they use has rebuilt already? Hundreds of thousands? Millions? Considering the number of water cooled cars Porsche has built, I'm sure it's quite a few more water pumps than Porsche has had done. I wasn't particularly happy with the way some of the stuff in regards to the rebuild was done on the Porsche rebuilt pump I recently bought. If I had to do it again, I'd go with the NAPA one.

 

I have successfully used rebuilt water pumps on my 944s so I did the same with my 928. Eight months later in my driveway, I heard the pulley coming off the shaft and working its way through my cover. Fortunately, I caught it in time before it failed. Next time, I will buy from the Big Three. And I may buy new. Close calls have a way of resetting your natural instinct to bargain shop. Every decision has a risk and a benefit.
My instincts now tell me that companies that specialize in a particular car are probably more careful about who they select to rely upon then the bigger companies that sell all kinds of parts for all kinds of cars to all kinds of people. These guys simply say "mail it back its still under the 1 year warrantee."

Off-topic, but what I would like to see more from the Big Three is safe option other than buying Porsche parts (for those of us that are a little less religious than others). For example, spark plug wires that are fine to use but don't cost $250, or a timing belt tool that doesn't cost $450, or motor mounts. This comment is not intended to offend anyone, simple to state my opinion as to what I am looking for.