5211 Leaking Fuel on top of fuel injection pump

[jhaltom]

I went out today to change all the fluids and get my 5211 ready for spring. Everything went well, but after running the tractor around for a little bit to check everything out, I noticed I have a pretty decent fuel leak coming from the fuel injector pump. Here are some pictures with an arrow pointing to where it's leaking: http://www.jeremyhaltom.com/zetor1.jpg , http://www.jeremyhaltom.com/zetor2.jpg. I can make it leak fuel from here by just using the priming pump. The engine runs fine, but it's a bit of a mess with the fuel oozing out.

I tried tightening the two bolts on top of the plate, but that didn't work. My guess is that there is some kind of O-ring or gasket between the pump housing and the plate that holds down the top part (Workshop manual wasn't very helpful). However, before I take this apart, does anyone know where I can get the replacement O-ring or gasket? Has anyone taken this off before? If so, any tricks I should know about?

Thanks!

 

[Renze]

IF you unbolt that, MAKE SURE TO MARK IT before disassembly.

The fuel injection per cylinder, is adjusted by turning the injector units in their housing. taking it off and not knowing its previous position, will cause that this cylinder will get less, or more fuel than the other two.

Are you sure it comes from under this flange, not from above ? It is not uncommon for fuel lines to leak a bit over time due to the intermittent pressure peaks at every injection, but these fuel pumps usually are never opened.

 

[jhaltom]

Thanks for the tip! Yes, it is leaking under the flange and not from the fuel line. If I pump the primer, I can watch the fuel 'bubble' out, so I know exactly where it is coming from. Do you know if there is a gasket or O-ring under that flange that I should be replacing? I don't want to take it off until I get the right part, since the tractor still runs (albeit with poor fuel economy!) and I need it to do a little mowing next week.

I looked over the Ridgeway website and there is a ton of O-rings, copper rings, etc. I'm just at loss on what to purchase.

 

[zetor3545]

be careful if you want to take the delivery valve out! not so much on undoing it but the small parts that are inside! and i you do take it out keep everything CLEAN! have you checked your injector pipes for fractures?

matt

 

[jhaltom]

Assuming that the injector pipes are the pipes coming out of the top of the unit I'm pointing at in my picture, then they are all ok.

I've found two possible part numbers for the gaskets, but no one has them in stock.

I'm down to two possibilities. First, I could take some JB Weld and seal all along the side of the flange (which is a 'hack' job for sure!), or I can go down and get some raw gasket material and try to make my own gasket. I'm a little nervous about unbolting the flange, since the workshop manual shows a ton of little parts inside and I don't want to goof anything up. But, since I'd rather fix the problem instead of putting on a band-aid, I guess this will be my only choice.

 

[Renze]

I have no idea what could cause your leaking, i've never touched a pump, only to open them up, not for repairs...
Maybe some of the other guys here could help you out...

 

[jhaltom]

Ok.. I guess an update to this saga is in order!

So, I took off the exhaust manifold so I could pop one of the pump shafts out of the housing. It turns out there is no gasket under the flange, but there are 3 o-rings along the shaft that seal in the fuel . They are almost impossible to find locally (they are 19mm by 2mm). I ended up buying some from Grainger, but they only sell them 100 at a time. Since all three shafts were leaking, I went ahead and replaced all 9 o-rings. Easy enough.

However, when I went to put it all back together, this is where things got interesting. Along each of these pump shafts, is a 'ring' that has teeth on it. These teeth engage with a shaft that runs down the side of each pump shaft and into the governor housing. When you move the throttle cable, this shaft moves forwards and backwards and 'twists' the ring on the pump shaft that adjusts how much fuel is pumped into each cylinder.

At first, I decided to put the throttle all the way down into the 'off' position and twist the ring on the pump shaft down to the minimum as well. I installed all three pump shafts, primed every thing (I have a 12v fuel pump in place of the crappy standard fuel pump, so it's easy to prime) and tried to start it up. No go. Turned it over and over and over and it never fired up.

So, I decided I'd do the exact opposite. I put the throttle at 'high' and twisted the ring on the throttle shaft to 'full' and installed them all this way. I hopped up in the seat to start her up and got one of the top 5 scares of my life! The engine roared to life at max RPM and there wasn't a thing I could do to shut off the engine! It was screaming and hollering and I was running around trying to figure out how to kill the sucker. I switched off the key.. No good.. dropped the throttle.. no good. I ended up quickly pulling off a fuel supply line. But, there was still residual fuel in the lines that look another 30 seconds (seemed like 30 hours) before the engine died. Yikes!

Next, after changing out my underpants, I decided I'd leave the throttle at the 'off' position, but put the ring on the pump shaft in the 'middle' position to see if that made a difference. Also, since I remembered that in a diesel engine, you only need fuel and air to run, I took off the top of the air filter and had a big rag ready to clog the air intake to kill the engine if it decided to go on a a tear again. Well, as you can guess, it went ape on me again, but this time I was ready and was able to kill it pretty quickly.

So, now the question comes in to play... How in the world do I put these crazy things back in and make this work! Has anyone ever done this before and can give me some pointers!? I'm kind of scared to work on the thing now. I looked at getting a whole new pump, but this one works fine and the price of the new pump is almost the entire worth of a 5211 in the U.S.

Thanks!

 

[dave_peters]

Just stopped laughing, Sorry.
When the throttle is on "shut off" position then the rack, which turns the piston barrels must be fully in the closed position.
Moving the throttle lever at all should then push the racK into the fully open position when the engine is stopped. this is how the governor works. it will only be pulled back into its lever related speed once the engine is started.
Working on these principles, and I stress I have never done this,
I would have the throttle lever at its stop position and the rack at its shut off position , as you did, but I would then open the throttle and make sure that the rack moved fully across to max immediatly. If not then try a tooth at a time until it does. I would suspect that there is quite a lot of "dead" area on the rack and that you had it just too far closed .
Hope this helps, I tried to look at it logically !!
Dave

 

[jburns]

As was stated earlier, turning the plungers in their bore is what adjusts each individual cylinder for the amount of fuel it gets in relationship to the other cylinders. Unless you market their positions when you took them out it is going to be almost impossible to get them back "right". If you did mark them you might be ok. I have never had an in line Bosch type pump apart and the rotary pumps I played with in school was 35 years ago so what I am going to tell you is a little bit of shakey theory. The theory would be to have the throttle (rack) in the closed position. Then all the plunger assemblies need to be in their original position, before inserting them turn the helix (the pumping thingy in the middle with the little gear on the end) all the way closed and insert the assembly. The idea is to have the rack all the way to off and have all the plungers all the way to off (they increase fuel delivery by twisting the machined helix to a wider open position). I'm just guessing at the procedure based on what I know about the workings of it. Not sure if that is even right. The way it works is that the rack rotates the plungers to vary the amount of fuel being injected. That is the little gear on the end of the plunger that rotates it. If you get that gear in the wrong polition to begin with it could be turned all the way off, all the way on, or somewhere in between. The little knurled part outside is made so you can rotate the barrel to adjust each individual cylinder so they all inject the exact same amount. This is all normally done on an injection pump test stand where they measure the amount of fuel being pumped by each cylinder into a measured flask. The rack limit screw sets the maximum total amount of fuel and the adjustments on each barrel adjusts individual cylinders so they are all even. Clear as mud????

Now the correct answer is to take the injection pump off the tractor and take it to any Diesel injection pump shop. There should be a number of them around, look in the yellow pages. They can calibrate the pump correctly. Make sure when you remove the pump that there is a timing mark to get it back in the right place. There will either be timing marks on the gear or there will be a spline that has a tooth missing so you can not get it wrong. If you do not get it back on right it will still not start.

 

[jburns]

Call a Diesel injection pump shop (they specialize in Diesel pumps and often turbochargers in the same shop), tell them what you did, and ask them what it will cost to get the pump calibrated. Hopefully it will not be too bad. If the quote floors you, do a search on eBay or Google. Several years ago I ran across a web site that was selling those Bosch look alike in line pumps for Deutz and Zetor tractors as well as others brand new for about what it cost to get a rebuild job done. Just FYI in case you don't like what you hear.

If you do manage to get it back together and it runs half way decent, there is one more possibility of getting the adjustment of the barrels right. I have heard of guys doing this many, many years ago. With the engine idling fairly slow, slower the better as long as it is not so low you loose oil pressure to the engine, loosten slightly the hold down bolt to each cylinder one at a time. It is possible to slightly turn each barrel and "listen" to the engine to make all cylinders fire evenly. What you are doing is fine tuning each plunger so it is injection the exact same amount of fuel as the other three. It will be painstaking because it is trial and error but is possible. As long as you marked the position of each barrel when you took it out, it should be pretty close to right and may not have to do this. If you only took one out, that one is the only one that might need to be "adjusted".

A Diesel shop is the safest bet, but also the more expensive.

John

 

[jhaltom]

Thanks for all the feedback!

I marked all the cylinders before they came out. Actually, the prior owner of the tractor did, by painting the engine and everything else with paint. When I took out the cylinders, based on the paint mark, I know within 1/16 of a mm where it goes.

I think the main part of my problem is I can't get the toothed rack (which goes down the side of the pump) and the toothed ring on the pump shaft to line up correctly. There is a 'missing' tooth on both the rack and the ring that I thought I was lining up, but maybe I missed it. I'm going to give it one more Texas try, but if that doesn't work, there are quite a few diesel shops around Dallas that say they will work on this pump. I'll let you guys know how it turns out.

Thanks again!

 

[jhaltom]

Ok.. My tractor is finally back up and running! I thought I'd pass over a few things that I learned during this experience.

First, don't bother taking the pump to the local Diesel shop (at least if you're in the U.S.) since no one has the adaptors to actually run the pump to get it calibrated. Also, since the Motorpol pump isn't a regular item that the techs see, they don't know how to put it back together properly. The local Diesel shop took the pump apart and when I got it back, the engine would start and run up to 1500RPM max with a ton of white smoke out the back. I had a mechanic come over and we tested the injectors, compression , and all that stuff and it was all fine. We checked the timing, but it turns out you can't really screw up the timing that bad. As long as the toothed gear between the pump and engine fits, you're at least with a few degrees of proper location.

The right way to fix the pump (at least for those of us in the U.S.) is to mail it to Petr at Zetor North America. For an extremely reasonable price they rebuilt the pump, replaced/reconditioned several pieces, replaced the hand pump, and tuned the thing right up. The tractor has never worked so well! I also over tightened the bango bolt for the oil line, breaking the bolt in half. Petr mailed me a new one at no cost! Talk about service! With this type of service, I can't figure out why Zetor's aren't just roaring off the showroom floors.