Back in my younger happier days I had a shrimp boat with a 471 Detroit and a Twin Disc hydraulic reduction gear. Worked perfect in forward gear but had to be babied in reverse, or pressure would drop to zero. In the off season I pulled the gear and disassembled everything. Looked perfect in every way. I gave up and went to a factory authorized repair shop. I had minimal to no funds and told the mechanic my issue. He agreed to take a look at my pile of parts and also said it looked as good as new. He was holding one of the clutch drums and shaft in his hand and was spinning the drum on the shaft while talking. All of a sudden he said hey that's not right. The clutch drum was supposed to be a press fit on the shaft and it was the one that drove the oil pump. So when any extra strain was put on the reverse gear the shaft would quit turning and no oil pressure. He felt so happy to have figured it out he gave me a used drum and shaft assembly and sent me back to my boat. There are good people out there!

I live in England & have never used heavy machinery so I don’t know why I look forward to your videos so much but I do 👏👏👏🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁥󠁮󠁧󠁿

It's still hard to believe that something that pumps oil can wear out.

I worked on hydraulics in the USAF for almost 16 years. Your videos make me remember why I went into computer and network repair after the military. Military hydralic fluid was red and would ruin a uniform in minutes if you had a leak run down your arm.....fun times. Great repair and I hope you get the tracking worked out.

Regarding pumps. High pressure pumps, like the gear pump you have there or a piston pump, are what’s called positive displacement pumps. They essentially move cavities around, as you demonstrated. This means, that come hell or high water, that pump will move something, as long as it’s lubricated, and given enough input power and sealing forces, it’ll drive any pressure, because it will output a certain volume per revolution, no matter what. The part about restriction is just relative to flow. If you have a large enough pump, a 2 inch pipe is enough restriction to create a certain pressure. However, as pressure in a hydraulic system is similar to voltage, higher pressure is easier to handle than higher flows, so we usually aim for low flow high pressure. Usually there’s some component in a certain design that sets your maximum pressure, for example a certain seal that gets really pricey above a certain pressure because no one uses them except NASA. Then your working pressure for that system is essentially maybe 60% of that.

Loving the excavator videos. I mean this in the best way but I hope your excavator keeps breaking down so we get to see more repair videos! Major thumbs up for being willing to tackle these repairs.

5/19/23; ..(1/2) hydraulic pump trouble shoot, removal, excellent close up camera shots, clear 'show-&-tell' explanations, re-install (no leaks) & psi test/adjust up to 3500 psi...all like factory new! Excellent video Jon! Your mechanical, video & verbal articulation make your channel A+ ! Stay safe & carry on!👍👍👏👏🔧⚙️💪✅️😊

Good to see the Yanmar's content generator is still in good shape! 😂

I watched your vid on the stihl weedwacker yesterday. Today i fixed a guys 12 volt positive displacement waterpump for his camper van. The limmit switch got stuck and did not cut out the pump if the pressure got too high and his pressure relief valve kept on opening. Opened the limmit switch and saw the small plastic button melted on the contact due to too high pressure that caused the pump to pull too much amps. I made a cad drawing of the little button, 3d printed a new one out of abs, replaced it. And it works like a charm. Adjusted the pump pressure to below 200kpa, wich is the pressure rating of the pressure relief valvle.

First off I love the fact that you have caps and pulls for all your hydraulic fittings. Second please keep doing these video's I really like your comments as your working on things. Your understanding of how things work is impressive.

Who else was waiting for the infamous “seal” picture to pop up @ 23:00? 🙋🏼‍♂️

Seeing all of those internal parts brought back a flood of memories for me. I spent a summer in college working in the shipping department of a hydraulic pump factory and was always fascinated by what we were manufacturing.

Thanks for the teardown and rebuild. Your narrative is informative and straightforward pretty much on point

Very happy to see you got the pressure back AND that it was a lot more excessable! Looking forward to the tracking.

Looks like someone sold that excavator just in time! 😂

Concise, clear, entertaining, and well produced, as usual. Thanks. 👍💯

Always fun swapping out bits to see if/where the problem is moving to. Works in so many fields and can save a lot of work if you get lucky. Thanks for the video and cool trick with the vacuum.

I use the vacuum trick when replacing valves on fuel oil tanks.

Every time you take apart the broken thing and explain why it was broken I learn so much. Thanks!

Thank you for all the effort that goes into explaining the details on the projects you get into. You really teaches us a lot . THANKS

Another successful repair after a spot on diagnosis !! But of course. John. that's all you do !!! A+ again for the best mechanic for anything that moves !!!

Thanks...good vid. I've run a lot of equipment...but your explanations of the mechanics are so straight forward that your videos are a pleasure.

Jon, Your videos are among the very best "weekend warrior" jack of all trades type on you tube. Thanks for taking the time to show us wanna bees a few new tricks. And more especially you share your mistakes and we all learn from them.

You’re definitely a jack of all trades and a master of many….I always enjoy your videos , keep them coming !!

Thank you for taking the time to explain how and why the pump failed. This was a really interesting video.

Such an excellent job! I'm learning so much about hydraulics from you!

I've got probably a more than average understanding of hydraulic systems. It was nice seeing your breakdown and troubleshooting process. We learn something new everyday. Thanks

Man, I love being off on Fridays! I get to watch so many of the channels I love right away.

Appreciate the excellent work and presentation! Always enjoy seeing the cows too!

Hey great job both troubleshooting and replacing that gear pump! I'm not a farmer, nor any kind of hydraulics mechanic (know only what you've taught us in vids) but really enjoy watching all your videos. In my opinion you are definitely one of the best KZfaqrs out there, hands down! I think a lot of the reason I enjoy your videos so much is because I'm a lot like you in the jack-of-all-trades sense. I strongly believe that everyone should be as self-suficient as possible and that way too many people throw away thousands of dollars paying mechanics for things they could learn to do themselves. I know not everyone is mechanically inclined, but those who are can save a Ton of money not to mention peace of mind knowing exactly what was done and how. Another great video! 🎉

You are a patient, patient man aside from the dishwasher 😊 Steve

Way to go John ,A mechanic for the ages Job well done no short cuts on trouble shooting and a good call on the pump that scoring and galling ,Dirty oil and filter will do it every time

Another great video. The amount of time and effort you put into your videos is amazing. They are very thorough and very informative. I have done many of the projects that you are now tackling and I really wish I had your videos. Well I was trying to do mine lol. Keep up the great work you are becoming one of the KZfaq greats.!

Wonderful work and it is so enjoyable to watch you figure out the problem

I love the vacuum trick. I learned it in high school working at an oil change shop. The number of times that we had someone comeing in cus they had a cross thereaded drainplug. Best part is the tamper seal was always from Wallmart.

Super video, your explanations are crystal clear , so easy to understand, thank you from Ireland🇮🇪☘️

Another video I just couldn't lay the phone down on. Great job. Thanks for keeping me entertained on a Friday evening

I really enjoy how you actually mention prices of parts in your videos. Some will complain but I think a lot of people understand that whether you overpaid or underpaid compared to so-and-so's brother's price it's valuable info and to be taken with context of time period and location. Keep it up please.

It amazes me as to how smart you are. Thoroughly enjoyed this video, thank you.

😂😂😂 The Greg Judy throat cleaning @20:35 had me laughing my head off. Please tell me it was intentional. I guess because we are about the same age, all of your humor works on me. Thanks for another great video to start my Saturday morning off here in Tokyo, Japan. Lots of construction and excavators around the city. Because of you and Diesel Creek, I enjoy watching them more than I ever did. Love the content, brother.

Congrats FC101, on finally getting the Gear Pump replaced and working again. now onto the tracks..

Similar issue I am experiencing is my Bobcat E80's one side track lacks much power than the other side. It turns well off ground and the travel gears seem good. I am going to be exploring my options. Your videos are encouraging to me thank you.

another great video! I'm a diesel mechanic and I've been using the vacuum cleaner trick for years. works good in the cooling system too, I use a small wet vac and made a vacuum chamber from a new gas can to catch any coolant that gets sucked up.

You have probably saved yourself a million dollars in your lifetime in labor cost...what a work ethic

What you are willing to take on amazes me! Keep up the awesome content!

Another top quality video...your videos are not only entertaining but absolutely educational step by by step and methodical based on pure knowledge and extensive research and thorough testing and examination backed with enthusiasm and hunger for knowledge. Job well done .yanmar excavators are known with quality and durability but it look like this one had a hard life and neglect like any other heavy equipment machine out there ...I am sure you will fix this machine and you will bring it to its former glory ..it will serve you for years to come ...looking forward for the next video to fix the tracking problem.keep up the good work .God bless.

That pump you mention around 29:30 is also known under the name "Gerotor pump". In case someone has difficulties looking up how it works. They're pretty fun, and also used in hydraulic steering systems, like in a tractor or for the articulated steering system in a wheel loader (directly connected to the steering wheel).

Love the vac trick :) I can totally see that kind of thing being useful for future hydraulic type work. Hard drive magnets are soooo useful. I have 2 or three big peanut butter jars full of them, and use them for all sorts of useful tasks.

Good to see that cam gear hanging out at the shop

Your channel is informative and very interesting, good humor to boot. Keep it up and best wishes.

Excellent Diagnosis witch helped me on my project of a Cat D5m lgp dozer transmission gear pump problem.

Great use of the vacuum at 11:30. I do the same trick swapping the hydraulic filters on my tractor. I always wonder if I should rig a reservoir before the vacuum itself, but never heard of anyone oiling their shopvac so ....

don't know a thing about hydraulics bit you make me understand it. Week after week. Thank you for that! Looking forward to next friday.

It's always nice to see a video from you. Best wishes from Denmark

Great job on the pump. Beautiful Angus cattle too. My uncle had an Angus stud on his farm here in AUS , beautiful cattle, unless you wanted to ear tag a new born calf and mumma got a bit upset, then it was watch out !!!

I am developing patience by watching you work.

Best explanation of how a gear pump works

I just spend 32 minutes watching someone I'll probably never meet fix a part I'll never need for a machine I'll never use, just to watch a mini-excavator do pushups. And enjoyed every minute.

Thanks for making these videos.. it is great to see what farmers do.. and how to fix these machines. Very enjoyable while not a mindless waste of time. I like your excavator.. it seems very nice and easy to work on

Thanks for this video. I think this will help me in the future with my Clark forklift.

Ive had to change the odd hydraulic power steering pump on one of our coaches ,good job done !

As a mechanical engineer, I couldn’t agree with you more about pump dynamics. You are a very intelligent man!

I have learned a bunch on your channel, you show the mistakes, bobos, talk through the process of what you are doing👍👍

I would recommend a magnetic hook with a string or bungee cord holding the gauge.

Great job and a brilliant explanation for the viewers

Dang you are good. Thanks for showing us this. It's always interesting to learn from you. That tracking issue sounds like it could be a real challenge. This machine is getting the treatment and once you are done it will be a good machine I think.

Got to be a great feeling of satisfaction with a succesful repair.

Great video very informative. Enjoy watching cause I learn something every time Thank for showing

Love the videos, helps me to work on my tractor’s hydraulics. Like all of your videos super informative.

Always liked these gear pumps. They last and are almost bullet proof. Then with so much equipment run by people that do not own them you must have a maintenance schedule. Maintenance goes a long way. Clean fluids and filters save money. Good Video! thanks

Another informative video John. But one question-where are the pictures of the good seals?

Hi Jon, very good many thanks, from UK.

that vacuum trick was genius!

John, every time you tighten or loosen a bolt I find myself saying “click”…. Loving it!! Keep the vids coming! From Australia!

ALWAYS a real pleasure watching you exercise your 'right to repair' and you always do a real fine job of it. Well, you trip over something now and then, but it's all part of the process. (grins)

Love watching your content!

John, don't take this the wrong way, because I know it's causing you grief, but I'm so happy your shit keeps breaking ♥

@18:57 It wasn’t as bad because you got stronger from the last one. Lol Love it….. Great content!!!!!

great work love watching you its so refreshing

Love these Videos! I look forward to them every Friday! I also like the brief segues to the cows. I’ve watched some interesting video shorts about a someone playing a music instrument for the cows and they all come running over to listen. I think that would be some interesting and fun content if you tried that with your cows. Keep up the good work!!

Love your videos like this. Super interesting to learn about and see how it all works. Thanks man.

Another great video! Thanks for the detailed explanation. Scott

I do enjoy tearing down and troubleshooting all hydraulic bits and bobs. It's amazing how such tiny things can be issues in them despite the normal conditions they operate under. More often than not it's as simple as an oring or wear, always in the most inconvenient spot. Hours or days of labour for a 0.00001 cent part 😅

Good video Jon, very interesting.

It's interesting that something that controls huge machinery can be so delicate.

I completely agree with your comments about the pump making pressure. I have run across folks making those same comments about oil pumps in gas engines. Some people grab a hold of stuff on the internet and just love to argue in circles. Haha. Appreciate all of your work putting out these videos. Makes my day when I see a new one released!

I look forward to your videos .... thank you. Hi from Claudio from Italy. 😉🇮🇹

Great educational video. Thanks!

I wanna point out in case anyone is interested or was wondering... So Kayaba is the company that makes pretty much all the mini excavator and compact machinery pumps, or at least all the Japanese ones. The name of the company is now KYB. You'll see that logo on the pump in this video. Yes, they're the same KYB that makes high quality shocks and struts for cars, trucks, and recreational vehicles and motorbikes. I think they're the largest manufacturer in the world for hydraulic shocks. They actually make gigantic shocks like 30ft tall for stabilizing tall buildings and underground mines. Hydraulic pumps and cylinders made in America or elsewhere in Europe borrow heavily from the original Japanese design. Back when computer aided lathes and other manufacturing equipment was primitive, the Japanese were able to mass produce parts with high enough tolerances consistently for hydraulics. That's why when people say Japanese automobiles or machinery is better quality than most other brands, they're not talking out of their asses. Nowadays even Chevrolet is manufacturing in the micrometers of tolerances range, so it matters less for newer models. But it makes sense why 1980-2000 model Japanese mini excavators are favored by people because those machines can be had relatively cheaply while still offering a quality design that CAT, CASE, and the John Deeres of the world have only recently been able to match.

So far I've watched every episode you've done on this and there's only one piece of advice I can give "Never sell it as its like brand new" Boy you've been patient with it. Do you like spraying as well ? as it would look lovely with a new coat of paint :) Honestly Jon, I am blown away with the level of workmanship shown here, you are indeed very knowledgeable and very interesting to listen to as well. I'm fairly new to your channel and have loved every video you've done so far. Keep them coming.

Nice work.

I use an old Dyson for a shop vac, along with a "regular" one. Works great.

Ah yes! I love your digger repair videos the best!!

Wow. What amazing sound in this video. Really, it is great.

I used to want a mini excavator. I am beginning to second guess that need.

i always learn so much watching your videos. thanks sincerly

Great video as usual sir. Big Momma report was a welcome one. That balloon piece was interesting. I feel the same way. I graduated from a college located in southwest Va. A little southwest of Roanoke.

Good job. Very educational explanation 👍👍

Criss cross applesauce. Crossing over your lines to see if the problem follows the controls or stays with the hydraulic drive motor I see. Good way to find what is the problem.

thanks for posting, I really enjoy this content on your channel.