CAV pump leaking

TJ in KY

Member
I have a AC 175, Perkins 4 cyl engine. I was at the farm yesterday and started it up and it ran for maybe 5 seconds and quit, like it rainout of fuel but had at least a half tank.. I thought I would bleed the system, bled at both bleeders on pump, and then went on to the injectors. I could not get any thing to bleed out at the injectors but noticed it leaking at the lever for the throttle control. (picture attached)

mvphoto12139.jpg

The screwdriver is pointing to where it is leaking. Sorry it is upside down, I have tried to flip it but can't figure out how too.
mvphoto12140.jpg
 
Every one that I have found like that. Needed a pump overhaul. Plenty of fuel in and bleeds out ok. But no fuel to injectors.
 
There are O-ring on those shafts that get hard or torn and will leak...and they can let air into the system. Any rebuild shop should know what size they are. Carefully take the cover off and watch how everything is put together. Pull shafts out from inside and replace O-rings, carefully put back together making sure gasket is placed right. You will then have to bleed the system, starting at the first filter. They can be tricky to bleed, follow the directions in the operator's manual.
 
The o rings are quite easily replaced, plus the thin paper
gasket under the housing.
BUT
Ensure you are very careful removing the cover and noting
which hole the spring is in etc etc. Make sure it goes back
together the same way and you may be lucky with the pump.
Often they will leak at those spindles, but not affect the way
the tractor runs.
Rx
 
The leak is not a hard fix, actually its a DIY with the right guidance..
Sounds like the metering valve is stuck or the fuel filters are dirty.
If the MV is stuck in the shut off position, you could try this.. While spinning the engine and the lines loose at the injectors and the throttle wide open, move the shut off cable rapidly in and out 5-6 times.. now look to see if you have any fuel to the inj. lines. IF NOT, its time to lift the top cover on the pump.. You can get the 4 orings and 2 hold down gaskets and a top cover gasket for around 11.00.. but you could get a complete gasket kit for about 22.00 P# 7135-110.
 
Here is a cut and paste of my old post on this years ago. Tom
Is your pump a CAV? If it is a CAV, I have been there done that. The CAV is prone to leaking around the throttle shaft and the cut-off shaft. First you will need to get 2 or 3 cans of engine cleaner. Clean, clean, and clean again the whole area. After each spraying, hose off, let dry and do it again. Cleaner the better, if you drop a ball of grease/dirt into the top while the cover is off - big trouble, one piece of crud dropped into the bottom of the pump will cost you about $600-700. Now using a paper towel, start looking for your leak; it will show up real easy on the dry, clean paper towel.
1. MOST important thing is to have some paper and pencil BEFORE you take off the cover.
2. Remove shut-off linkage and throttle linkage.
3. Remove screws or nuts holding lid on.
4. DO NOT just lift up the top. Lift it just a little, very carefully so you can peek under it. A spring is attached from the lid to the bottom part of the pump. One end of spring is hooked on a wide post looking like a tombstone. The tombstone has several holes in it. Write down which hole the spring is hooked in before you remove it. The other end is through one of the holes in the flattened end of the control rod. Again write down the hole it is in before you remove it. This step is VERY IMPORTANT. If the spring is not reassembled to EXACTLY the same holes on both ends, the tractor will never run right again. The same pump can be used on different model tractors with the only difference being how the spring is hooked. My MF dealer mechanic can tell the proper holes by using the 3 numbers on the CAV. Now remove the spring, and lift off the lid.
5. Write down the model/year of tractor, and the model of the CAV pump and serial number. There are 3 different numbers on my CAV pump.
6. Take the cover with you and head to MF dealer and purchase a new gasket and four (4) tiny o-rings that fit around the throttle shaft and the shut-off shaft. Each shaft has 2 o-rings. If the o-rings are not leaking now, they soon will so replace all of them. Total cost of gasket and 4 o-rings is about $5 or $6.
7. You will need a little patience and two extra hands to get the spring attached on both ends and the new gasket fitted. I did this complete procedure on my MF 690 and now it has NO LEAKS.
Tom
 
If the pump has many hours on it the best repair is to reseal the complete pump. I've seen too many times other leaks show up shortly after, head O ring, drive seals, etc. that require removal anyway. When the throttle/ stop shaft seals leak other seals are usually right behind getting ready to leak too. At least that has been what I've seen. Patch jobs usually bite the backside later when it needs done again.
 
Thanks for all the replies, good how to write-ups and troubleshooting tips.
The tractor has about 3200 hours on it so I don't know which way I am going to go with it. Try to fix it myself or take it somewhere for a complete rebuild. It had been running fine it hasn't really been used much in the last few years. I will look at it again the next time I am out at the farm.
 
Mine has been leaking on my Ford for about 5 years. No big deal,
makes for a messy looking tractor, but it works and at my age in
life that's what matters. So I just use it. Doubt it would leak a
gallon of diesel in a year. Even if it leaked 10, that sure beats the
uncertainty and cost of tearing into it.

Mark
 

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