[J Davidson]

I have a Belarus 420A. Hyraulic oil ran low, now loader works but is very is very weak. 3PH not responding at all. Probably 2 separate issues.Any suggestions on where to start to get these problems cured?

 

[pogobill]

Welcome to the forum. There are a number of members here that are familiar with the Belarus tractors that will surely give you some help.

 

[J Davidson]

Welcome to the forum. There are a number of members here that are familiar with the Belarus tractors that will surely give you some help.

I hope so. Thank you.

 

[Belarus/MTZ volunteer]

I hope so. Thank you.

Hello and welcome to the forum.

There are loads of reasons why hydraulics are leaking in MTZ/Belarus, some of them are:

• Low quality of rubber coils, they also get damaged by occasional metallic burrs. Silicone coils are recommended, sometimes. As well as sealant.
• Damaged or poor quality hydraulic distributor, but do not rush replacing it, you will likely have two poor quality ones. Start inspecting with engine turned on

I would suggest these tips for ANY MTZ/Belarus tractor and related brands, like Vladimirets or LTZ (which 420A seems to be)

Load something reasonably heavy (for 420A with 57hp, it's probably 0.6t) on your loader and wait till oil heats to 40-50C, then set maximum crankshaft RPM and do around 10 ups and downs of loader. But, as you say, your loader is very weak, so it will lift the load more than 4-6 seconds, probably.
In this case, start checking piping. If a high-pressure pump is weak, it will be hot, as well as piping nearby. If it's a distributor, then all bigger diameter pipes will be hot.

If you see foam from hydrotank, then there's air leak, check piping tightness and generally inspect for damage.
It is very likely that main filter of hydrosystem is malfunctioning, specifically, its safety valve. If the case, then the pressure will force oil to leak from every direction.

Now, if your loader is moving, but not smoothly, it's probably a malfunction of spool return valve.
These universal post-soviet tractor tips would be enough to start, I think. Hopefully, you will be able to fix it with making your own coils or with string and sealant.

Also, there is slight hell in Belarus designations for export, if you could give a photo, it'd be easier to identify actual manufacturer and years of production and find a relevant manual.

Cheers.

 

[BinVa]

Not familiar with the 420A specifically but it could be as simple as air in the system, since the system was run low. As stated...cycling the loader full up/down multiple times will force the air thru the system to be released from the hyd. reservoir. If filter was replaced..be sure it was reinstalled correctly. Keep an eye on the fluid level and top as needed. Where is your fluid leaking? Is it external? Where from? B.

 

[J Davidson]

Not familiar with the 420A specifically but it could be as simple as air in the system, since the system was run low. As stated...cycling the loader full up/down multiple times will force the air thru the system to be released from the hyd. reservoir. If filter was replaced..be sure it was reinstalled correctly. Keep an eye on the fluid level and top as needed. Where is your fluid leaking? Is it external? Where from? B.

Have not found any leak but without a shop fluid doesn't show on the ground very well

 

[BinVa]

Does the 420 have a hyd pump disengage lever? If so..is it completely engaged. Any cavitation noise from the pump?

 

[BinVa]

You may also want to post your question on the Belarus/MTZ site. There has not been alot of activity lately...but brand specific and lots of knowledgeable participants.
WWW. MTZtractortalk.com