# airlessco 4100 slow stroker rebuild



## Ophoff Painting Co. (Aug 14, 2012)

I am currently in the process of rebuilding an airlessco 4100. Is there any documentation or videos on this one? I have more packings in my kit then what I pulled off, and I seem to be missing some key components.

The problem is we had a guy do the maintenance on some of our pumps, and it seems likely that the issues I am running into are a result from him.


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## SprayRepairGuy (Jan 15, 2014)

This is a useful website for looking up repair parts.

Here is the reference for your pump. There are also 1500 other references listed for all manufacturers.

Here is the link for the manual for the 4100.


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## mr.fixit (Aug 16, 2009)

what spray guy said. he has it all covered


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## SprayRepairGuy (Jan 15, 2014)

The unusual thing about the 4100-style pumps is that they have the reverse packings on the bottom of the lower stack that act as a pre-wiper of the sleeve wall. Notice that the open end of the V-Packing faces away from the internal pressure chamber. Perhaps these are the packings that you think are extra?


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## Ophoff Painting Co. (Aug 14, 2012)

It's the upper stack that was missing from the pump. Along with the male and female glands. There was something els in it's place.

Ill see if I can get a picture of it.


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## Ophoff Painting Co. (Aug 14, 2012)




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## SprayRepairGuy (Jan 15, 2014)

That is definitely not the upper packing set per the manual. It appears to be some kind of spacer/retainer or guide. If you remove it from the rod, is the upper packing set retained inside of it? It's hard to tell from the picture, but is the protrusion at the bottom the male gland of the stack? Remove the stack from the bottom of the retainer. Does the upper packing nut look the same as in the diagram? If the upper packing nut is different than the one shown in the manual, perhaps Airlessco came up with a two-piece design. In any case, you most likely need to replace the packing sets, so go out and purchase a new repair kit - either an Airlessco 187-040, or Bedford 20-1815.


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## Ophoff Painting Co. (Aug 14, 2012)

Here is the inside. I have the Bedford kit which is how I realized that something was wrong.

The other issue I have is that I can. It remove the bottom but for the lower valve. It spins hard but does not move. Is it not threaded?

And the upper valve I replaced some parts, but nothing matched up there either. Kinda looks like they pieced pieces from different pumps together.


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## SprayRepairGuy (Jan 15, 2014)

Yes, those are the packings inside of the retainer. Remove them and replace them with the ones from the Bedford repair kit. You should have six packings plus the male and female glands. Your pump is obviously different than the version pictured in the manual. Are you sure it's a 4100?

The lower valve housing is threaded. If you unscrewed it and it just continues to rotate, yank it off. It's probably just being held on by the o-rings against the threads or dried paint. The diagram in the manual does not show o-rings, but again your fluid section is obvious different.


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## ptm (Oct 20, 2011)

2nd what he said, I went through the same thing with a 5100sl.


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## straight_lines (Oct 17, 2007)

This thread is part of what makes PT a great site. Kudos to the repair pros for helping this guy.


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## SprayRepairGuy (Jan 15, 2014)

In digging around, I think I found your fluid section. The attached diagram is for a 4500 fluid section. It has the upper packing retainer that you have pictured above. It also uses the o-ring sealed intake retainer. You can find the manual here.​


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## Ophoff Painting Co. (Aug 14, 2012)

That looks about right. I am going into the shop today so I'll verify the number.

I am still missing both male and female glands on the upper stack. I bet the last guy who rebuilt the pump threw them out on accident. Can those be purchased?


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## SprayRepairGuy (Jan 15, 2014)

Yes, both the male and female glands for the upper packing stack can be purchased individually from any Graco dealer - part numbers 187-025 and 187-026. In Airlessco's infinite wisdom (now Graco's), neither of these parts are included in the 187-040 repair kit. 

However, from your picture it looks like at least the male gland is there, protruding from the retainer at the bottom of the stack.


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## Ophoff Painting Co. (Aug 14, 2012)

The pump is a SL 4100.

I think you are right about the male gland. Is it possible the fluid section was swapped out with a 4500 or maybe the pervious guy just didn't know what he was doing?!?

Thanks a lot for your help. Really appreciated!


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## SprayRepairGuy (Jan 15, 2014)

The repair kit, piston rod and cylinder are all the same for both fluid sections, as well as most of the parts. You can use either upper packing nut configurations. The last time the pump was repacked, the shop probably had the updated parts in stock.


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## slinger58 (Feb 11, 2013)

Not trying to hijack the thread, but when you say "slow-stroker" is that like the old Graco EH 333 & 433 ?

Just curious.


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## Oden (Feb 8, 2012)

slinger58 said:


> Not trying to hijack the thread, but when you say "slow-stroker" is that like the old Graco EH 333 & 433 ? Just curious.


Slow stroker to us is a big pump. The slow stroker has that big piston. It slow strokes. It's pop........pop.........pop........pop
Little pumps on the other hand go pop.pop.pop.pop. they're rushing to try and keep up.

Got nothing to do with the make or anything. It's the stroke.


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## Epoxy Pro (Oct 7, 2012)

Oden said:


> Slow stroker to us is a big pump. The slow stroker has that big piston. It slow strokes. It's pop........pop.........pop........pop
> Little pumps on the other hand go pop.pop.pop.pop. they're rushing to try and keep up.
> 
> Got nothing to do with the make or anything. It's the stroke.


I didn't know this myself. I was always wondering why our big sprayer was more of a slow pop than like the smaller sprayer faster pop. This make sense now. Thank you Oden.


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## slinger58 (Feb 11, 2013)

Oden said:


> Slow stroker to us is a big pump. The slow stroker has that big piston. It slow strokes. It's pop........pop.........pop........pop
> Little pumps on the other hand go pop.pop.pop.pop. they're rushing to try and keep up.
> 
> Got nothing to do with the make or anything. It's the stroke.


That's what she said.:jester:


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## slinger58 (Feb 11, 2013)

I got it, Oden. Like the Graco Bulldogs and Kings.


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## SprayRepairGuy (Jan 15, 2014)

It's simple... The bigger the diameter of the rod and/or the longer the length of the stroke, the greater the volume of paint that gets pushed to the gun for each cycle. Before Titan came out with the 440's the smallest airless on the market was the Binks Humdinger which had more than twice the stroke of the 440 - meaning, for the same amount of paint sprayed from the gun, the 440 pump had to make more than twice as many cycles. One of the trade-offs is that with short cycle machines you gets the convenience of a smaller package, but due to the number of cycles you have much greater wear of the components. Today's smaller machines are very capable and very portable, but I get complaints all the time about how they just don't last like the older bigger machines. A lot of it has to do with the stroke since the packings on smaller machines travel over the same section of piston rod many, many more times to pump the same amount of paint of a bigger sprayer.


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## Ophoff Painting Co. (Aug 14, 2012)

Put it all back together today, but the packing nut would not seat properly. Turns out the cylinder is slightly warped. Looking down the inside of the cylinder I can see a gap on one side. Do you know where I can get a good price on a new one?

Do you know what causes this?


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