Fixing old high pressure washer

[Turbo]

I’ve not seen many bronze fittings on pressure washers in the last 40 years.

Me either.

 

[DennisCA]

Been an abnormally busy week here so I hadn't had time to work on the washer, but last night I found a sized chunk of hex brass stock in my post box, courtesy of someone who has read about this in a local forum I also post about this project .

So I should be able to make a whole new part now.

 

[Turbo]

I acquired yet another pressure washer motor/pump unit, a hawk pump coupled up to a 3hp Brooks single phase motor.

Spend a while tonight sorting out some bad inlet plumbing, will hopefully get to try it out later.

 

[DennisCA]

First test, but without a hose or handle. I found a few leaks where I didn't tighten up properly. And the new hose barb for the inlet leaks, it was broken looking but I tried anyway, the original barb is for 3/4 garden hose and I have only 1/2" garden hose. The welded unloader valve leaks unfortunately from where I did not fix it, as well as though the gasket I figured was torched. I tried starting it and it "pulsed", I figure with no nozzle on the front and an unloader valve that's on the fritz that's about what you can expect. I saw no leakage from the pistons.

So I need a new hose barb for the inlet, make a new part for the unloader valve and a nozzle simulator (some threaded insert with a hole. I am not sure, is 075 = .075 inches?)

I wonder if 1/2 hose is enough though to supply this washer or if I should go to 3/4 hose all the way?

 

[Pete.]

A 1/2" hose should be ample from a tap. The 3/4" might be needed if you were gravity feeding from a tank.

 

[awemawson]

Run you hose into a bucket and time how long it takes to fill, thus determining your flow rate. Knowing your flow rate compare it to the pump rating and you will know for sure.

I know mine is 17 litres per minute as it was insuficient to cool my induction furnace so I had to take other steps !

 

[carbon]

1/2" hose should be fine. As the unloader valve is leaking air will be drawn into the inlet side of the pump and cause the pulsing. As a simple check if you have a fitting blank the inlet manifold were the return line from the unloader fits.


Then leave the return line disconnected from the pump, fitting a blank should stop any air being drawn into the inlet side of the pump. As this is a four cylinder pump the output should be fairly smooth

 

[DennisCA]

I didn't have one unfortunately, it's how I wanted to test it first, with the unloaded valve bypassed. But it's probably as you say.

 

[DennisCA]

I'm probably just gonna buy something like this for a handle package. I've spent all week looking at handles, lances, hoses, nozzles without finding something that met all my criteria. Inside Finland it seems basically impossible to find everything at one place, with the right specs (3/8 hose, 1/4 lance, screw in nozzle), or if I did find something it was "hell no" money.

This uses Kränzle M22x1.5 fittings and the nozzle uses some kind of barrel nut and o-ring, which is apparently a Kärcher style fitting. I think that'll be good enough. I would try and standardize to Kränzles parts anyway as they got one of the best reps for quality and both brands seem to be the most prevalent in Finland. It's no big for me since the fittings for the hose need replacing anyway so I might as well get one for M22x1.5.

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[DennisCA]

Making a new part, and oh my brass likes to fly everywhere. I had to rig up some shields to contain the mess. Feel like I should vacuum this up into its own bag and save it for melting down.

I ground a new tool for brass turning and it's working real well. I used another tool with a top rake at first and it didn't work well at all, it was HSS, but it was also a cheap grade without cobalt so it might have been partial reason.

I bought a batch of NOS blanks with cobalt a while ago though so I ground a simple tool with no top rake and it worked great. I'm gonna have to grind a 55 degree threading tool as well, already have a 60 degree one. I grind these with no top rake as well.

And no / neutral top rake means they won't have a tendency to dig in like I found happened with the carbide inserts, which mostly just caused me grief. If you got a worn screw or nut (or both) on the cross slide that can be an issue when threading I found, with a positive rake it sometimes dug in.

 

[DennisCA]

Ran into something weird when working on this part, I was checking just what kind of thread it was. I was expecting a 55 degree BSP thread. But best I can tell I have a 55 degree thread with 1.5mm pitch.

Is that even a thing that's existed at any time? But the 55 degree gauge fits perfectly into the threads, as does the metric 1.5mm.

 

[Pete.]

55 and 60 degrees are not so easy to tell apart with a thread that fine.

 

[awemawson]

PG thread dimensions seem to combine Imperial and Metric sizes and pitches - could it be a PG ?

 

[DennisCA]

I think Pete's right, went and rechecked all dimensions and the tool I used for checking 60 degree was more like 63 so it threw off the fit. Between a verified 60 and 55 it's very hard to tell a difference. So most likely it's a normal metric thread after all.

 

[DennisCA]

New part almost done, there's still the need to make an o-ring groove on the inside bore, I also managed to get .4mm thicker walls on this by being careful with the fitting of the spring that goes on the inside, a nice sliding fit instead of a sloppy one. Should make it stronger than the original.

 

[DennisCA]

I machined the o-ring groove last night after I found a piece of HSS to turn into an internal grooving tool and finished the part but I forgot pictures.

Now I just need a new hose barb connector for the inlet manifold. I've been wondering though if the inlet manifold needs to be remade from scratch. For some reason it's built from a steel box that's corroded on the inside and that can, no pretty sure it will cause pieces of debris to make its way to the cylinders eventually even though I've cleaned it out now.

Should've been made from stainless or brass. Possibly aluminum could work. It would also be easier to work with on the bottom if the pipes going to the inlets of the cylinders where flexible hoses instead of solid pipes. It's a very exact fit or everything won't go together again so if I made a new manifold I'd have to make it exactly like the old.

But I am not feeling the motivation right now, need to end this project and clean up the shop and begin my summer projects:
-Clear out my shed floor, prep the floor for casting a slab
-Prep the outside for another slab outside the door
-Insulate the shed walls, doors, ceiling, put up OSB sheets on the walls.
-Move all my woodworking tools from garage to shed, including a heavy cast iron band saw and table saw.

 

[Guzrik]

I machined the o-ring groove last night after I found a piece of HSS to turn into an internal grooving tool and finished the part but I forgot pictures.

Now I just need a new hose barb connector for the inlet manifold. I've been wondering though if the inlet manifold needs to be remade from scratch. For some reason it's built from a steel box that's corroded on the inside and that can, no pretty sure it will cause pieces of debris to make its way to the cylinders eventually even though I've cleaned it out now.

Should've been made from stainless or brass. Possibly aluminum could work. It would also be easier to work with on the bottom if the pipes going to the inlets of the cylinders where flexible hoses instead of solid pipes. It's a very exact fit or everything won't go together again so if I made a new manifold I'd have to make it exactly like the old.

But I am not feeling the motivation right now, need to end this project and clean up the shop and begin my summer projects:
-Clear out my shed floor, prep the floor for casting a slab
-Prep the outside for another slab outside the door
-Insulate the shed walls, doors, ceiling, put up OSB sheets on the walls.
-Move all my woodworking tools from garage to shed, including a heavy cast iron band saw and table saw.

And you need to clean your lathe

Great project, fully understand you want closure now.
Maybe cobble some hoses together as temporay solution for manifold?
Edit: copper tube soldered?

 

[DennisCA]

Oh yeah I got most of it, but I need to do a more thorough clean. I have a separator on my shop vac and put it on a different bucket for this, so almost all the brass I got separate ad stored in a container. Some day I will melt it with other scrap and make plates or round bars or whatever.

I will leave the manifold for now.

 

[DennisCA]

I tried it again today, the universe has conspired against me this week trying to get time to go buy one so I put the original back and put some 3/4h hose on it and then I managed to get a 1/2 fitting not leak on a 3/4 hose with the aid of a hose clamp...

The unloader valve works, mostly. I was able to make it release and to adjust it until it doesn't. However there's always a slight flow of water. I suspect an o-ring I replaced is slightly too small but it was the closest I got. There's an o-ring and a part that moves near where the brass part meets steel.

I melted this with the tig torch and then I drilled a 1.5mm hole, closest I got, I believe 1.8mm is what I should have for 075.

I shut off the return line by using the deleted detergent mixer, it also leaks a little.

I adjusted the unloader valve until it didn't release but I suspect with a 1.5mm hole that's higher pressure than intended. It produces a strong jet but there is still a slight pulsing when active. I wonder if the slight leaking from the unloader valve and the small leaks from the return line is what causes it. Or maybe it just works this way.

 

[carbon]

As the unloader valve works you can connect the return line back to it then try it again. Any leaks because of the detergent control or unloader will then be eliminated. Any leak from the unloader will be returned to the inlet side of the pump.