Hydraulic Filter Change Problem

ponytug · Nov 28, 2020

If you have already tried a second filter, I would try tightening the hose fittings on the filter, and on the pump. I would be very surprised if they were loose, but strange things do happen. Be careful not to torque the hoses when you try to tighten the ends; you need a wrench on the hose, and a second wrench to do the tightening. (You probably know that, but just in case...)

I would then tighten the second filter another 1/4-1/2 turn. If that doesn't work, I would also have another close look at the sealing area on the filter housing for the gasket, and blow it out with brake cleaner, then air to clean it out.

All the best,

Peter

m5040 · Nov 28, 2020

They don't call them hairline cracks for no reason, very hard to notice. Dont want to hijack the tread, but what does everyone think about if he actually started the engine by using the Deutz shutdown lever to keep it from starting (not unplugging the connection) and as the engine was cranking, slowly move the shutdown lever to the run position. This would attain a less then idle speed. Then he wouldn't damage the starter. It would take a helper to watch for air. Just a thought, something I would do to preserve the starter, but I actually take out the spark plugs on my 180 PT just to make it turn faster and easier.

joshlee · Nov 28, 2020

So John, your saying about running the engine in order to purge the air out of the hydraulic pump? Just today and yesterday I probably put more wear on the starter than the four years I had it.

m5040 said:
They don't call them hairline cracks for no reason, very hard to notice. Dont want to hijack the tread, but what does everyone think about if he actually started the engine by using the Deutz shutdown lever to keep it from starting (not unplugging the connection) and as the engine was cranking, slowly move the shutdown lever to the run position. This would attain a less then idle speed. Then he wouldn't damage the starter. It would take a helper to watch for air. Just a thought, something I would do to preserve the starter, but I actually take out the spark plugs on my 180 PT just to make it turn faster and easier.

joshlee · Nov 28, 2020

I went around to most of the fittings, hoses, couplings, that are connected to the filter housing lines, and the oil filter seal with shaving creme while I cranked the engine, as means of trying to find the vacuum leak. The shaving creme was undisturbed at all the places I checked so far. I'll try to finish up the rest of the places tomorrow. The oil filter gasket doesn't have a vacuum.

This is an important question because it will greatly narrow down the possibilities of where the leak is, so if anyone has an answer, please let me know. Is this vacuum leak coming from only the suction lines that are attached to the hydraulic filter housing? Or could the vacuum be coming from almost any fitting/hose/coupler etc. that is attached to the hydraulic pump?

Thanks again.
Josh

ponytug said:
If you have already tried a second filter, I would try tightening the hose fittings on the filter, and on the pump. I would be very surprised if they were loose, but strange things do happen. Be careful not to torque the hoses when you try to tighten the ends; you need a wrench on the hose, and a second wrench to do the tightening. (You probably know that, but just in case...)

I would then tighten the second filter another 1/4-1/2 turn. If that doesn't work, I would also have another close look at the sealing area on the filter housing for the gasket, and blow it out with brake cleaner, then air to clean it out.

All the best,

Peter

ponytug · Nov 28, 2020

joshlee said:
I went around to most of the fittings, hoses, couplings, that are connected to the filter housing lines, and the oil filter seal with shaving creme while I cranked the engine, as means of trying to find the vacuum leak. The shaving creme was undisturbed at all the places I checked so far. I'll try to finish up the rest of the places tomorrow. The oil filter gasket doesn't have a vacuum.

This is an important question because it will greatly narrow down the possibilities of where the leak is, so if anyone has an answer, please let me know. Is this vacuum leak coming from only the suction lines that are attached to the hydraulic filter housing? Or could the vacuum be coming from almost any fitting/hose/coupler etc. that is attached to the hydraulic pump?

Thanks again.
Josh

Hi, yes, you are only looking for leaks on the suction side of the filter. Anywhere else will leak, or spray, oil.

Shaving cream, while creative, probably isn't thing to use to find an air leak as it will get sucked into your oil.

Random idea, and definitely a YMMV idea: I have had one JIC fitting crack, about forty hours into use. That would cause an air leak if it were on the suction line.

All the best,

Peter

P.S. @m5040: I believe the logic on not running the engine to purge the oil is to limit heat build up in the un/under-lubricated charge pump. I don't know for sure.

ponytug · Nov 28, 2020

m5040 said:
They don't call them hairline cracks for no reason, very hard to notice. Dont want to hijack the tread, but what does everyone think about if he actually started the engine by using the Deutz shutdown lever to keep it from starting (not unplugging the connection) and as the engine was cranking, slowly move the shutdown lever to the run position. This would attain a less then idle speed. Then he wouldn't damage the starter. It would take a helper to watch for air. Just a thought, something I would do to preserve the starter, but I actually take out the spark plugs on my 180 PT just to make it turn faster and easier.

I like the idea of removing the spark plugs. Brilliant! It is a great compression release.

And definitely +1 on hairline cracks. They are really hard to find.

All the best,

Peter

m5040 · Nov 28, 2020

The vacuum leak problem can only occur on the hose assemblies that exit both sides of the hyd filter. One goes to the tank and one goes to the pump. The problem can occur anywhere with these items.
I worry about giving some advice that needs to be used with caution. This is that kind of advice, think it over and fully understand before you attempt it. If you remove the filler cap on the hyd reservoir and make a plug/adapter, it can be pressurized with somewhere around 2 psi, maybe up to 3 or 4, but you would go up very slowly and look for the hyd tank expanding. You are dealing with pounds per every square inch and it ads up. When you pressurize it, you will have to wait for hours but you may notice the leak(s). You will need an accurate gauge and look/listen to the filter can and the hyd tank for bulging. You don't want to burst it. You may just want to drain the tank and take off the suction hoses and filter housing, examine on bench under bright light maybe with magnifying glass or just replace with new parts. Loctite makes a special tread locker/sealer for use in hyd systems. If you go that route you might want to use it. Just some thoughts. Running the engine at a slow idle was just my idea to make 110% sure you indeed have a problem.

SpringHollow · Nov 28, 2020

I almost always have a hard time getting the filter to not leak on two different PT1850's. There are two different types of seals available for my filter, one "L" shaped in cross section and one just rectangular. Sometimes one works better than the other. But I almost always end up crushing the filter some trying to get it tight enough to not leak. I just purchased a large metal band clamp to see if it works better than a normal strap wrench.

Ken

joshlee · Nov 29, 2020

I FOUND THE PROBLEM!! It was a tiny crack in the hydraulic filter housing. I unbolted it and was inspecting it under 4X magnification and seen two places where there were very tiny cracks. Neither one of them looked like a "smoking gun" to me, but I put a small dab of shaving creme on the one ( Ponytug, I tried using oil but it was too hard to see ) and turned the engine over to watch the bubbles come out the hose. To my amazement the bubbles stopped! I went over and looked at the shaving creme and a little bit of it got sucked in! I cleaned it the best I could and put a dab of high strength Locktite on it and turned the engine over again; no bubbles. So, I closed everything up on the pump and am going to order a new hydraulic filter housing tomorrow.

All of you guys (Ken, John, Ponytug, Mossroad, Oosik, Cqaigy), I want to say thanks for your help. Some of you have helped me out multiple times with issues, I appreciate it.:thumbsup:

Josh