Yongheng Fail: crank arm shred and a warrantee nightmare

[FlexWagtail]

My YongHeng 110v machine siezed after a couple of months of use amounting to about an hour of total run time. Seller ShareProfit dissapeared from Amazon after refusing my demands for return, replacement or authorized repair. Amazon wouldn't cover it. I bought an extra SquareTrade warrantee which did cover the loss, but only after I had to threaten them with a complaint to my state's Attorney General Consumer Affairs Division. Bottom line. Big headache.

Soooo, now that I have nothing to lose, I decided to take the thing apart. I found the failure point that Joerg Parva (Slingshot Channel) discussed at about the 20:00 mark in his YouTube review https://www.youtube.com/watch?v=7NdnItyJs-U.  As Joerg predicted, the aluminum crank arm spalled badly at the connection to the steel main crank resulting in seizure. (pictures attached). I want to note the oil level and condition was good and the cooling system was functioning when the failure happened at about 3800 psi.

I've ordered a new crank arm off AliExpress and plan to try a repair after polishing off the residual aluminum spall melted onto the steel crank connection.

Any advice on how to conduct the polishing and repair would be appreciated.

 

[Phreedom]

I'm surprised about your SquareTrade experience. I've always heard good things about them. What was their reason for wanting to deny your claim?

 

[dirtbikerick]

Flex that crank throw looks toasted, I build engines for Porsche, not having my eyeballs there, I new con rod and a mic to measure stuff out I can't say for sure but it looks like it's recycle time. Does the con rod have any oil holes drilled?, it's either bad machining, material quality, lack of quality lubricant or design. So enough negativity, let's pretend we live on a farm and it's the 30's, if you want to try to repair it get some 1200 emery cloth or wet/dry sandpaper and come in from the top and see what you can do, when you have metal transfer, (aluminum onto steel) you will have to get the aluminum off 1st then focus on polishing the crank throw, then go down fine in numbers until you get to crocus cloth. Keep rotating the crank as you go, work a spot, rotate, and so on.

 

[FlexWagtail]

"Phreedom"I'm surprised about your SquareTrade experience. I've always heard good things about them. What was their reason for wanting to deny your claim?

By way of background because this was an Amazon deal, so SquareTrade had an electronic record of all information about the transaction, and all communication with the seller via Amazon's internal mail system -- so there was no question about the claim, the seller's response, and costs. Regardless, they refused the claim outright. Instead they demanded that I find a repair facility and get the machine fixed at my cost and they would then consider reimbursing me IF the facility met their standards. Of course, there are no authorized factory repair facilities for YongHeng in US, and SquareTrade could not recommend an facility that met their standards. I found a machine shop in my area who determined he had no access to standard US parts for the compressor, and who said the time and effort involved with fixing the machine exceeded its value. He declined to take the machine and provided an invoice/work order stating his opinion. I provided the documentation to SquareTrade (via .pdf scan) and the claim was denied again. This time they said it was because the document was "not computerized" (it was, obviously, or how could I have sent it to them?). I hit the cieling. More phone calls, etc. They finally gave in when I pulled the Attorney Generals' card. They're not running a charity, and I don't expect them to hand out $100 bills without documentation -- but my experience proved that I had to do hours of work to recover the loss.

 

[FlexWagtail]

"dirtbikerick"Flex that crank throw looks toasted, I build engines for Porsche, not having my eyeballs there, I new con rod and a mic to measure stuff out I can't say for sure but it looks like it's recycle time. Does the con rod have any oil holes drilled?, it's either bad machining, material quality, lack of quality lubricant or design. So enough negativity, let's pretend we live on a farm and it's the 30's, if you want to try to repair it get some 1200 emery cloth or wet/dry sandpaper and come in from the top and see what you can do, when you have metal transfer, (aluminum onto steel) you will have to get the aluminum off 1st then focus on polishing the crank throw, then go down fine in numbers until you get to crocus cloth. Keep rotating the crank as you go, work a spot, rotate, and so on.

The connecting rod (which I called "aluminum crank arm" in OP) is being replaced by a new part from China. It has an oil hole drilled in it and a little channel on the interior circumference designed to spread oil. All that stuff if spalled out in the original part. Perhaps I should order a new steel crank too rather than trying to polish? The reason I didn't go that way because I couldn't get the damn thing off. There's an allen bolt looks like holding it in but I couldn't get it to budge. I don't have an impact driver or whatever tool I need to get it loose. Advice?

 

[dirtbikerick]

It's probably locktighted, So get a micro torch, get the head of the Allen (and crank) hot, not red hot, jam the crank with a block of wood, get helper buddy to hold and see it it comes loose, you can always drill the head of the Allen off, remove throw and then remove remaining bolt.

 

[Bleudg]

Flex, I have worked on several air compressors with that rod configuration and they had a 1 inch protrusion or pin at the base of the rod that acted as an oil “dipper”. It looks like your rod had this and it was broken off. Can you see if that is the case. I have seen these rods galled up an frozen when that dipper is gone. The dipper is what splashes oil and lubricates the journal 

 

[FlexWagtail]

"Bleudg"Flex, I have worked on several air compressors with that rod configuration and they had a 1 inch protrusion or pin at the base of the rod that acted as an oil “dipper”. It looks like your rod had this and it was broken off. Can you see if that is the case. I have seen these rods galled up an frozen when that dipper is gone. The dipper is what splashes oil and lubricates the journal 

You are exactly correct. The dipper was busted off and laying in the pan. Have no idea why it would break as there is nothing for it to hit. Have you been able to replace rod with ease?

 

[prfssrlee]

Sorry to hear about these troubles. Hopefully your new piston/arm will get you back up and running.

Since you have the connecting rod replacement on order, I wonder if you could machine out the hole a bit and buy the right sized sleeve bearing to fit into it before replacing it onto the crank shaft. Or maybe even just a bronze bushing - that should be alot better than bare aluminum on steel.

 

[FlexWagtail]

"prfssrlee"Sorry to hear about these troubles. Hopefully your new piston/arm will get you back up and running.
Since you have the connecting rod replacement on order, I wonder if you could machine out the hole a bit and buy the right sized sleeve bearing to fit into it before replacing it onto the crank shaft. Or maybe even just a bronze bushing - that should be alot better than bare aluminum on steel.

It crossed my mind to find a bearing that would fit the crankpin journal, but I have no access to machine tools to drill out that rod to mate it. As Bleudog pointed out, the dipper that oils the rod was broken off, thus depriving the crankpin journal of lubrication causing the sieze. New rod will restore that function as well -- as long as I get that crankpin polished nice and smooth. So I'll pass on the bearing since it's not designed into the original. It's all Chinese junk as far as I can see. But if you don't let it get to you, its fun enough to tinker with. The last laugh will be on me if I get it running again and then find out all the dicking around has caused leak in one of the many bolts and connections that I have undone to get it apart! Solving that will be a joy, no doubt. But I'm not there yet.

 

[Bleudg]

Yes, I have cleaned and polished the journal as described above (just enough to remove the aluminum debris) then install a new rod. I have had pretty good luck doing this with the lower pressure oil lubricated compressors. Not sure how much more load that HP piston and 4500 psi pressure puts on the journal. Worth a try!

 

[stephen2258]

Hey Everyone, Steve Kenyon here from "PCP Compressors, the Good , the Bad & the Ugly". It looks like Flex got the BAD & the UGLY. I'm always sorry to hear when a YH owner has a nightmare of a problem. From everything I read you got the best advice I think you could get anywhere. Did you ge a full refund of your money? I read that you got some compensation from your aftermarket insurer. Was it enough to buy a new machine or just enough to buy the parts to try to fix it? If you have the money for a replacement I suggest you buy a Tuxing from TXfactory. They are probably the best seller we have found on Ebay. They sell Tuxing's for $280. including free shipping. They also are fast to respond to problems and questions.I am currently running a YH I've had for the past year, notone problem. I also have a new Tuxing sitting unopened in the garage waiting for the day the YH quits running. Harold Sobel, one of the most knowledgeable guys in our group says in his opinion the Tuxing might be built a little more robust than the YH. He also said that the two compressors are identical when it comes to parts. He has repaired a cooked YH with parts from a cooked Tuxing and the machine ran perfectly. He has also bought the twin cylinder Tuxing and says it is more than twice as good as the single cylinder model. I think he paid $599. from TXfactory on Ebay. Lastly, I just want to mention that there is a lot of expertise from the members of the "PCP Compressors" group to be found if anyone else needs help.

 

[Brian10956]

I so happy I waited and got a better compressor or I’d be in same boat. Those Chinese dealers have it in their business plan to go out of business every 2 months and they open under a different name not just in the compressor business in all businesses . I used to work for a software/ hardware company. We actually stopped getting components direct from China we switched to Taiwan and Israel. Not that they are necessarily more honest but the Long arm of the law can get them if they do illegal business practices.

 

[dirtbikerick]

Even though I spent way more than I wanted my carette compressor has run flawlessly, not rubbing this in your face flex cause I feel your pain, we all have bought stuff that took a dive way too soon and dealt with it. The tuxing comp sounds like the way to go if on a limited budget. But this carette really does its job well.

 

[kingrude1]

Wonder if this is your crank? If it is, wouldn't cost much to just replace it. Might contact seller and see if this one fits the Yong Heng. Good luck.


https://www.aliexpress.com/item/4500PSI-PCP-compressor-single-cylinder-compressor-spare-parts-crankshaft-rotor-1-pcs/32836565672.html?spm=a2g0s.8937460.0.0.AOGxOX

 

[Kayakairgun]

Flex, dont worry to much. You just got a lemon part no biggie. Most likely the rod or crank was made out of spec. They make whats called plasti gauge to check your rod, crank clearances. I would recommend checking your clearance, shoot for .0015 to about .005, these are ballpark #'s. Google how to do this, or you will be back into her in a short time again. One other recommendation, if you dont have the right tools to work on the pump then get them. I've screwed up more crap in my life with the wrong tool than I care to admit. lol 
Best of luck with your pump.

 

[Wepop]

You can get the aluminum off the rod with 
muriatic acid.
We use it when repairing small air compressors.
We do Jenny warranty and others.
Use heavy rubber gloves when using. In a well ventilated
area.
Use a little on the end of a rag. Do not get in on anything
Other than the steel crank. You may have to do a couple
Times. I clean with water. I would lay wet rags in the 
Bottom when applying. 
I use 1500 sandpaper to polish.
You can get muriatic acid at lowes and the sandpaper at
Advanced Auto.
The acid will not harm the steel, but it will give it a 
brown color on the surface.
I would do it outside. It will smoke and put off bad odor.

 

[FlexWagtail]

"Wepop"You can get the aluminum off the rod with 
muriatic acid.
We use it when repairing small air compressors.
We do Jenny warranty and others.
Use heavy rubber gloves when using. In a well ventilated
area.
Use a little on the end of a rag. Do not get in on anything
Other than the steel crank. You may have to do a couple
Times. I clean with water. I would lay wet rags in the 
Bottom when applying. 
I use 1500 sandpaper to polish.
You can get muriatic acid at lowes and the sandpaper at
Advanced Auto.
The acid will not harm the steel, but it will give it a 
brown color on the surface.
I would do it outside. It will smoke and put off bad odor.

I’m about to do this job according to your instructions. I really appreciate post. Do you recommend any sort of lubrication on the crankpin before reassembly? 

 

[FlexWagtail]

update: BIG FAIL
The piston rod on my Yong Heng seized. There is a dipper on the rod that mysteriously broke, thus depriving the crankpin of oil. I ordered a new piston assembly from Ali Express for only $20 BUT…… The new assembly second stage piston did not fit in the Yong Heng. The new part had 4 plastic rings, and the original had three. They looked identical in diameter, but in fact the new second stage piston was a few thousands too large. “Okaaaaaay…..” sez me. “We’re not done yet.” I took apart the new assembly and moved the new rod to my old original piston set to replace the original rod that seized. This time the reassembly went smoothly. But after about a 3 minute run under no load to wear in the new rod I got a catastrophic failure. The failure point was where the first stage and second stage pistons are connected. I tried hard, but I’m done with Yong Heng. Even if yours runs great for a while, it will need a rebuild. I could not find a reliable source of correct parts. Without that, you’re screwed at some point down the road. 

 

[Eaglebeak]

Sounds like the parts that you got were for the Tuxing pump. My understanding is that the four ring high-pressure piston is used by Tuxing and it is possible to bolt the whole top end of one to the other but not just the pistons. Swapping just the small piston to the wrong large one may or may not have caused your Hemorrhage. I think that the whole top end including the piston, rod, barrel, head, and fittings can be had for about $100 USD. I hear your pain but it might be worth one more attempt as long as your crank pin is serviceable and even that assembly is available. Have you tried the Yong Heng Shop on Aliexpress?