# Airlessco LP540 repack



## ChristhePainter (Aug 30, 2014)

Hi everyone. I'm new to this forum. I'm a painter/painting contractor from Wichita, KS. I have a couple of questions.

I just picked up an older Airlessco LP540 with blown packings for $410. I was going to have HomeDepot re-pack it but it would've taken them a month or more to get it back to me. Sherwin-Williams is too expensive and would take the same amount of time, so I'm going to re-pack it myself. I've never re-packed a sprayer before. If I follow the directions in the manual it doesn't look too painful. 
Can someone who has re-packed an Airlessco lp540 tell me if it takes any special tools? I saw in the manual that I needed a "packing adjustment tool". Is that a tool that comes with the new packings? Is it a necessary tool or can I use something else?

Thanks for any help.


----------



## robladd (Nov 22, 2010)

After you have repacked it and ready to start the pump set the upper packing nut by hand it's also where you put the throat seal. 

At the lowest pressure possible to move the piston cycle pump saver through the prime spray valve and prime your pump. It only takes 1/8 turns to stop leaks. When you get a leak turn off your pump and relieve the pressure give it a 8th turn and charge the system.


----------



## SprayRepairGuy (Jan 15, 2014)

From your post I gather that you already have the Airlessco manual for the LP540. If not, you can download it from this link. The Bedford parts reference for the pump can be found here.

There is nothing difficult in repacking the pump. Follow the instructions in the manual.

The "packing adjustment tool" is a device that Airlessco sells to adjust the upper packing nut without messing it up with wrench marks. Use a pair of channel locks instead if you don't have the tool.:whistling2:



robladd said:


> After you have repacked it and ready to start the pump set the upper packing nut by hand it's also where you put the throat seal.
> 
> At the lowest pressure possible to move the piston cycle pump saver through the prime spray valve and prime your pump. It only takes 1/8 turns to stop leaks. When you get a leak turn off your pump and relieve the pressure give it a 8th turn and charge the system.


Not following a procedure such as this is one of the common mistakes made by users. The tendency is to over-tighten the upper packing nut. ONLY tighten the packing nut until the pumps stops leaking. As the pump is used and the packings begin to wear, use the packing nut to further stop the leak. Over-tightening only takes away future adjustment and shortens the life of the packings.


----------



## robladd (Nov 22, 2010)

SprayRepairGuy said:


> From your post I gather that you already have the Airlessco manual for the LP540. If not, you can download it from this link. The Bedford parts reference for the pump can be found here.
> 
> There is nothing difficult in repacking the pump. Follow the instructions in the manual.
> 
> ...


 If you have read the owners manual it says to set the upper packing nut hand tight and then give it a full 3/4 turn. I have found that it does not need to be that tight to stop it from leaking. Mine is set at 2850 PSI. I go hand tight then 1/8 turns till it stops leaking. It usally only takes a 1/4 turn to stop it from leaking. I have had mine for 20 years and when I do adjust it I can't turn it any thing less than about a 1/8 turn. Nice rigs they run forever.


----------



## SprayRepairGuy (Jan 15, 2014)

robladd said:


> If you have read the owners manual it says to set the upper packing nut hand tight and then give it a full 3/4 turn. I have found that it does not need to be that tight to stop it from leaking. Mine is set at 2850 PSI. I go hand tight then 1/8 turns till it stops leaking. It usually only takes a 1/4 turn to stop it from leaking. I have had mine for 20 years and when I do adjust it I can't turn it any thing less than about a 1/8 turn. Nice rigs they run forever.


I fully agree with your method, and quoted your post as a good example of the proper way to approach adjusting the upper packing nut. I was just expanding on what you had said, not disagreeing with it. The key is not to ever over-tighten the nut - and that goes for just about any pump, any manufacturer.


----------



## IHATE_HOMEDEPOT (May 27, 2008)

I would also suggest trying to determine if the piston has excessive wear. You will might be able to notice this by eye but if you have a caliper that would be good. I am not sure of the tolerances but if the piston has a dip in it (worn depression) you might have issues. In other words a new seal won't seal properly.


----------



## ChristhePainter (Aug 30, 2014)

Thanks for the help and the tips guys! I've just finally gotten around to the repair.

I've cleaned and inspected the piston. It feels smooth to the touch, but on visual inspection I've noticed that it has some very slight scratches and dimples in it that are so slight they're not noticeable to the touch. Is it absolutely critical that the piston be perfectly smooth and flawless? I don't want to ruin a brand new set of packings. Also I can't get the outlet seat unscrewed from the piston to inspect the O-ring and outlet ball inside. I can hear it rattling around though... Is that good enough? Is it critical to inspect the outlet ball and o-ring that's inside of the piston?

Here are a few pics of the piston.


----------



## robladd (Nov 22, 2010)

WTF have you been spraying? Thats a new piston all day long


----------



## ChristhePainter (Aug 30, 2014)

HAHA... good, I wasn't sure... I haven't sprayed anything yet. I just bought it with blown packings.
I got the outlet seat retainer unscrewed from the piston but now I can't get the outlet seat and outlet ball out. Any tips on getting those out?


----------



## robladd (Nov 22, 2010)

You'll have to soak it in solvent. When I said that's a new piston all day long, I meant you'll need to get a new piston.


----------



## ChristhePainter (Aug 30, 2014)

Ahhhh... !!! I have to do a job. What happens if I go ahead and use it with the new packings and then replace the piston after painting a house? Will it even work and will it ruin the new packings or shorten their life?

Thanks for the help.


----------



## robladd (Nov 22, 2010)

It will more than likely shorten the life of the new packing.


----------



## ChristhePainter (Aug 30, 2014)

So it will work then just to get me by on this house?


----------



## robladd (Nov 22, 2010)

ChristhePainter said:


> So it will work then just to get me by on this house?


Run it and see how you do. I repacked 1 like yours and it lasted a while. Those packing are rated for 2000 gals you will not get that with the condition of your piston.


----------



## ChristhePainter (Aug 30, 2014)

Thanks man. I appreciate your help!


----------



## SprayRepairGuy (Jan 15, 2014)

The retainer inside the piston rod has Loctite on the threads. Depending how aggressive the last installer was with applying the Loctite it may be difficult to get out without heat. Heat will break down the adhesion of the Loctite. Lightly heat the outside of the end of the rod with a torch, it will come loose pretty easily.

The circumferential rings on the rod are the result of leaving the pump pressurized when not in use - that's what leaves the "imprint" of the packings. Leakage erosion from normal use is usually in the form of longitudinal lines along the length of the rod. Never leave the pump pressurized overnight. That's a safety hazard, and causes erosion on the rod as seen here.


----------



## ChristhePainter (Aug 30, 2014)

Yeah thanks for the info. I have always taken care of my equipment. I just recently bought this sprayer from a pawn shop with blown packings and with dried paint all over the piston, the fluid body and the packing nut from it leaking out of the top of the fluid pump assembly... he gave me a good deal on it. I was hoping I wouldn't have to replace the piston too. 
When I was cleaning the dried paint off the fluid pump I noticed that the previous owner had even tried to stop it from leaking with some sort of silicone type filler?!?! It looked almost like silicone caulking or sealant. Imagine that.

I have a few final questions. 
1.) In the Airlessco packing kit there is a metal spacer with 2 holes in it. Do I need to line up those holes with the prime switch flow opening??? inside the fluid pump? Or are the holes in the spacer just some sort of pressure relief holes and their position inside the fluid pump body doesn't matter?
2.) I bought some Ultralube non-petroleum white lithium grease (biobased). Do I need to use that and spread around the inside of the pump body and on the packings before I put them in? Or can I just use throat seal oil to lube everything up with before assembly?


----------



## SprayRepairGuy (Jan 15, 2014)

The holes on the spacer sleeve can be aligned any way you want.

Plain old 30W motor oil does a great job soaking and lubricating the parts for assembly. No need for anything fancy. Definitely watch out for anything containing silicone - big no-no.


----------



## ChristhePainter (Aug 30, 2014)

Thanks!! :notworthy:


----------



## ChristhePainter (Aug 30, 2014)

Well I got everything put back together and tested it with water. It all seems to be running smoothly with no visible leaks. Except about every 3 seconds it cranks over one and re-pressurizes. Is the pressure leak because of the piston being bad or do the packings have to break in? I've always used Titan sprayers and they weren't constantly re-pressurizing.
And once I do replace the piston will I have to re-replace the packings again?


----------



## straight_lines (Oct 17, 2007)

A new piston is like $140, I would have gone ahead and done that when you had it down. I have had issues with the pressure sensor before on one of mine.


----------



## SprayRepairGuy (Jan 15, 2014)

ChristhePainter said:


> And once I do replace the piston will I have to re-replace the packings again?


If the pump is leaking at the piton rod because of the wear you indicated, then as the fluid passes between the rod and the packing it will erode material from either or both. Extended use will ruin the packings. When you get around to replacing the rod, if you reuse the now bad packings, you will still have leakage and ruin your newly installed rod.

Save yourself time and money by replacing both at the same time. There is hardly ever an instance where you would replace a rod and not the packings. But there are times when the rod is OK, and you only need to replace the packings.


----------



## ChristhePainter (Aug 30, 2014)

Thanks. I take it that it's likely the bad piston that makes it keep re-pressurizing every 2 or 3 seconds?
I just replaced the packings and have to spray a house. I'll be spraying about 15gals of primer and then about 10gals of paint. I know that primer is hard on sprayers... would spraying that amount of material be bad enough and considered "extended use" like you said? Would it warrant having to replace the fresh packings again when I replace the piston? 
I'm assuming that I should go ahead and replace the "fresh" packings again when I replace the piston... just to be safe?


----------

