water pump assembly question

[peg_pilot]

I am installing a new water pump from Dave Bean, and even after a conversation with them I am just not completely sure I understand which direction the washer that goes between the impeller and the non-rotating part of the pump seal faces. This metal washer has a rubber insert in its inner diameter. The rubber insert has a "top hat" cross sectional shape, i.e. a (very short) cylinder with a brim or shoulder on one end. There is a recess machined in one face of the washer that allows the shoulder of the rubber insert to sit flush with the washer surface. The rubber insert is not bonded to the metal washer, it is easy to push it out of the metal washer from the direction opposite the shoulder. My question is whether the shoulder end of the rubber insert should face the impeller or the non-rotating part of the pump seal. The consequences of getting this wrong are pretty horrendous, as I'm sure the seal would not work, the pump would fail in short order, and I would have to pull the engine and tear it all down again. So any advice would be greatly appreciated !

[ardee_selby]

I assume the DB kit is similar, if not the same, as these UK items:

"For illustrative purposes"...the partial assembly sequence is shown in the second pic.

Is that similar to what you are querying?

Components 1.jpg (9 KiB) Viewed 2489 times

HIH

Cheers - Richard

[billwill]

as above, The metal cup fits into the recess in the front cover (or the removable pump module) the smaller washer fits against the implellor. It is more or less the same diameter as the boss of the impellor, so that it does not obstruct the water flow. The smaller washer has its black carbon (or maybe white PTFE) surface in contact with the other part of the seal. It has to slip very easily at this point at 6600 RPM.

I usually put some gasket goo around the outside of the metal cup washer.

[peg_pilot]

The seal in the Dave Bean kit looks the same as the QED one, and I believe I have installed that correctly. However, the washer in the Dave Bean kit looks quite different to my eyes. I don't see that either face of the DB washer is more obviously suited to contacting a non-rotating surface, it appears to be one solid piece of material except for the rubber insert. Probably the shoulder side of the rubber insert should face the non-rotating part of the seal, so that water pressure will push the washer onto the shoulder ? I think that the other way around the washer might get pushed off the rubber insert, which would allow a lot of leakage.

Thanks for the help.

[billwill]

I guess you have to talk to Dave Bean's again, but perhaps a small thin disk of carbon or PTFE is missing?

[CBUEB1771]

Peg-pilot,
Did you buy a standard water pump repair kit from Dave Bean or one of his water pump cassette conversions which includes a new front cover and backplate?

[peg_pilot]

Russ,

I bought a standard repair kit.

[StressCraxx]

The washer with the white surface that slides on the shaft is alumina ceramic. It is lapped flat to less than 3 helium light bands. The carbon face on the spring is also lapped to the same flatness tolerance. 1 helium light band = 11 millionths of an inch. The ceramic face is bonded to a rubber washer that seals against the shaft and the impeller.

The white ceramic face must contact the carbon seal face in the housing when the water pump is assembled. The spring force holds the faces together, along with the water pump pressure and cooling system pressure. The coolant acts as a lubricant between the faces when the pump turns. A very tiny amount of coolant will weep across the faces during operation. Almost all evaporates. That is why there is a weep hole in the case. Do not plug the weep hole or the coolant will ruin the bearing.

The shop manual shows the assembly in the diagram too. Do not scratch or chip the faces, or the pump will leak.

Regards,
Dan Wise

[mini64]

someday was need to do an assembly diagram of these pumps as i do not see one in any manual that is clear enough for the un-initiated.

I've had the same question about this washer. The one supplied in these kits is not white on one side, it appears to have the same coating all over it, the only difference being the rubber "ID" seal seats in it from one side. I have always chosen to put this side down first on the shaft, as in away from the impeller. My reasoning is that is you put it on the other way the seal pops out of the washer as you press it down.

Interestingly my last rebuild kit, with this particular washer, also had a slinger. I thought they were obsoleted decades ago!

Also, with the two grooves on the bearing, you'll note you have to push the bearing in so the second groove lines up, not the first. the bearing will just be past flush in the nose end (pulley end). make sure you press it in with the long end of the bearing going towards the impeller.

[peg_pilot]

While the washer supplied in my pump rebuild kit does not have a white ceramic side, one of the faces appears to have been lapped to a very smooth finish, so from what Dan Wise said, this face should be pressing against the seal, not the impeller. And as mini64 said, this direction results in the washer pressing against the shoulder of the rubber ID insert as it is being installed, so preventing it from popping out. Mini64, have you had good pump longevity installing the washer this way ? Your use of the word "always" when referring to the washer installation direction could be taken to mean you have had to replace the pump many times !

Apparently there are a number of different versions of the water pump out there, which seems surprising. For example, my pump bearing has only one groove, and the people at Dave Bean told me not to expect it to line up with the groove in the front timing cover - making the retaining clip useless. I didn't get a slinger in my kit, what makes these obsolete ?

[billwill]

I cannot imagine what a slinger would do in the pump chamber as it is completely filled with coolant.


Sorry about thinking the white surface was PTFE, I'm not sure if I've actually seen one of those, I suspect that the ones that I've fitted were black on both surfaces, possibly both carbon.

[alan71]

from the workshop manual.

Alan.

[Elan45]

I got my kit from Burton last year and it came with a diagram showing how it was to be assembled, and it was different from the shop manual assembly. But the reason I went to Burton in the 1st place was that I wanted the newest non-cassette ideas on sealing this thorny issue. The kit from Burton was the latest ceramic /PTFE version and I am hoping it lasts far longer than the old Anglia kits I had been getting.

Roger

[StressCraxx]

I cannot imagine what a slinger would do in the pump chamber as it is completely filled with coolant.


Sorry about thinking the white surface was PTFE, I'm not sure if I've actually seen one of those, I suspect that the ones that I've fitted were black on both surfaces, possibly both carbon.

The slinger is installed between the pump mechanical seal and the bearing(dry side of the seal). It is there to "sling" any leakage away from the bearing and drain to the weep hole. I don't believe it prevents coolant from reaching the bearing at all. The bearing has lipseals at both ends to keep coolant out, as long as the lipseals last.

Regards,
Dan