Refreshing Comet AXD 3020G power washer pump?

[Craig in Canada]

I have a BE! power washer of unknown age and unknown hours in the family which was a freebie several years ago. It has a Honda GC160 and a Comet AXD 3020. I believe it would be the 3020 "G" version for 3/4" shaft. Comet says this is 3GPM, 2000psi @ 3400rpm.

It works well but the pump crankcase is experiencing water ingestion and I have to change the pump oil frequently. This unit works well, has cost very little and is probably worth servicing.

I know there are all kinds of pump designs and other considerations made by those more "in the know" than I, but I'd like to pick up some knowledge and, at the same time, not unnecessarily spend money on things I don't need or choose the wrong items.

Based on the fact that it's making good pressue but I have water ingestion I probably need a piston seal kit, right?

I see urls like http://www.shopetsonline.com/Comet-AXD-Series-s/665.htm list common rebuild kits under the pump. I've also looked at http://www.cometpump.com/MB_Pompe.pdf (page 40) from Comet themselves but I find the latter a little overwhelming.

Do I need a piston seal kit? How about the check valves? If it's making pressure I don't need those yet? How about the unloader, should this be serviced? Where are the best places to order that are located in Canada or ship to Canada without a lot of hassle? Anything else I should service while I'm in there? I've seen piston seal kits, "overhaul" kits, "maintenance" kits....what's what? (for instance, page 2 of http://www.deindustrial.com/v/vspfiles/V4_Backup/Comet-AXD-Series.pdf



Thanks!

 

[Gilitar]

Does the unit look like it has seen alot of hours? It may or may not be worth all the trouble.

BTW, Comet makes an excellent pump that is made to last.

 

[Craig in Canada]

Well, we've been using it for years without incident other than the fact that the crankcase slowly takes on water. I loaned it to a neighbour that put about 11 hours on it or something doing his fences. When I got it back the pump case fluid was over the sight glass. Generally it isn't as bad in my hands, I don't know just how much time he was running on the unloader and the like and when the most water gets in.

It was the general purpose washer at a local utility shop that was used for goodness-knows-what for who knows how long and serviced on an unknown schedule. But it was free and works great. Someone was trying to service the pump and put an o-ring back in the wrong place. My dad took the freebie, put the O-ring in the right place, and voila. Of course for all I know he interchanged two o-rings and it works but that's why it is taking on water - he didn't have any service instructions.

Before the season really gets started I don't mind some "trouble", but it would be more "trouble" if I wanted to use it and it was in pieces

Since there's still 5' of snow outside, I think I have a little time. lol I'd also consider a learning experience. It doesn't look like these things are booby-trapped to go "sproing" and shoot the magic pieces all over the workshop. Maybe I'm wrong about that.

It seems to me like the most basic kit is $40-$70 - I think it's worth that and a couple of hours of my time. If I invest any $ I might consider replacing the timing belt on the GC160 as well so it doesn't go and take the engine with it right after I rebuild the pump.

 

[Gilitar]

Originally Posted By: Craig in Canada

It seems to me like the most basic kit is $40-$70 - I think it's worth that and a couple of hours of my time. If I invest any $ I might consider replacing the timing belt on the GC160 as well so it doesn't go and take the engine with it right after I rebuild the pump.



I agree, it is probably worth a couple hours of your time. Good idea on replacing the timing belt.

 

[hind28]

well i work on most general pumps, and AR pumps, giant pumps, haven't done a comet yet but the problem your having with water getting into the pump case is piston seals, they are easy to do as long as you don't damage the brass case pulling them out.

 

[Craig in Canada]

Originally Posted By: hind28
well i work on most general pumps, and AR pumps, giant pumps, haven't done a comet yet but the problem your having with water getting into the pump case is piston seals, they are easy to do as long as you don't damage the brass case pulling them out.


Sounds good. Have you ever seen any online references on how to perform the job that are worth looking at? I can probably do a simple R&R without too many instructions but I don't know how critical any torque values may be , whether any kind of clearances need checking, if there are any booby-trapped areas, a particular assembly lube to use etc...

 

[hind28]

This link has the part numbers for the packing/seal kit and other parts, also make sure the rods that the packings ride on arn't scored. If the rods are damaged and u put new packings on them, they will fail prematurely and leak internally (water in pumpoil case). I prefer to use automotive grease as assembly lube, and for the torque specs or parts breakdown/instructions, u may need to call comet themselves and get them to fax it to you, cause I can't find it on their site.

http://www.cometpump.com/Comet-Catalog_07_LoRes.pdf

 

[Craig in Canada]

Thanks for the tips. As a first-timer (but with general mechanical experience) would you suggest that I disassemble the pump before ordering anything to figure out what's what and looking for things like scoring? If there is scoring or mechanical wear, these service kits would be a waste of time and money, right?

If only I could run across an online shop manual...

 

[hind28]

yea pop the brass case off and take a look just remeber how to reassemble it, also give comet a call or email and ask them send you instructions.

 

[hind28]

also take off the rod caps and make sure the seal are good.

 

[Craig in Canada]

Hi:

I put this job off for a while but I have now taken the pump apart to a certain extent and I'm looking into getting some parts.

My reference materials:

PARTS

PROCEDURES

From the parts diagram, I see that a piston seal kit comes with 32,33,62 and 63. It seems like the O-rings 32 are intact and fit very snug. One of the #63s seems to have come apart. The #33s installed inside of the #61s seem to drag on the pistons and seal OK (no water applied - just by feel).

I would think that the #34s must also be faulty in order to allow water into the case because 32, 33, 62 and 63 could all be shot but water would just dribble from the manifold if that were true, not get into the oil side of the system. I inspected the #34s and the area seems a little oily in that some grit has been attracted to the area, but there's no evidence of water etc...

There is a little bit of hard water build up in certain wet areas of manifold parts. There discolouration on the wet of the brass discs #61 and the corresponding area of the manifold - high temps, perhaps? I've used #0000 super fine steel wool to pretty much clean it all up. No marking or wear on the pistons at all. Other than some water deposits on the ends you can't even tell they have been run.


Recommended course of action? I was thinking of getting one of the 32,33,62,63 kits and then 3 stand-alone #34s because the kit that includes #34s also overlaps the first seal kit.

Or, I just keep using it and change the oil frequently if this isn't likely to fix the problem. I guess it pretty much has to with that many seals being changed - right?