hello Hello everyone - Zetor 7011 need help with breaks

[Gin77]

Hi everyone,
I'm currently working on my late father’s Zetor 7011 tractor, which holds a lot of sentimental value to me. It's been lying idle for the past 6 years, but I recently decided to get it back up and running. After replacing the battery, I was surprised (and relieved!) to hear it start up again!

However, I’ve hit a bit of a snag— the right rear wheel is stuck, and I’m trying to figure out the best way to get it moving. I’m still learning as I go, so any advice or tips on how to approach this would be greatly appreciated!

Looking forward to connecting with others who share a passion for restoring and working on tractors.

Thanks,
Sean

 

[Joachim]

Hello and welcome Sean!

You made a mistake there, you shouldn't remove the plate with the 4 screws, if the mechanism behind it falls apart you will hardly be able to avoid removing the whole portal, because you can normally only put the mechanism back together if the portal is removed.

If your brake is stuck - have you first checked whether the wheel brake cylinder is simply stuck?
When was the last time you changed the brake fluid (DOT 3 brake fluid)?

 

[Gin77]

Thank you so much for pointing out where I went wrong, I really appreciate the advice! I haven’t changed the brake fluid yet. Do you think draining it and trying to drive might help release the brake? It could help rule out the handbrake issue.

I also read that there’s an adjustable nut under the matt in the cab, just above the half axle, that can release the handbrake tension—does that sound right to you? Would love to hear your thoughts!

 

[Joachim]

Do you think draining it and trying to drive might help release the brake?

No, not realy.
You can check the break pedal adjustment, if there is no play, its possible that the fluid cant float back to the Brake fluid reservoir.

I also read that there’s an adjustable nut under the matt in the cab,

Thats only for handbreak adustment.

that can release the handbrake tension

right

does that sound right to you?

Yes, but if you start fiddling with it without a plan, especially without knowing whether the handbrake OR the footbrake is on, you will only adjust the handbrake and possibly make things worse.
The workshop manual describes in detail how to adjust the handbrake.

Therefore: BEFORE you disassemble and/or adjust everything, first check whether the handbrake is not already loose. To do this, remove the gill plate so that you can look at the brake drums from above. The plate is only secured at the front with an M6 screw.
If the brake band is loose, so that you can move it back and forth a little with your screwdriver, the handbrake is not to blame...

 

[moliner]

Zetor brakes tends to get stuck if they are not used for a longer period of time. Normally it's the brake cylinders getting stuck because of rust.
Zetor brakes have a bad reputation, but I think it's a bit unfair. The brakes actually work great, if the tractor is being used frequently.

 

[Gin77]

No, not realy.
You can check the break pedal adjustment, if there is no play, its possible that the fluid cant float back to the Brake fluid reservoir.

Thats only for handbreak adustment.


right


Yes, but if you start fiddling with it without a plan, especially without knowing whether the handbrake OR the footbrake is on, you will only adjust the handbrake and possibly make things worse.
The workshop manual describes in detail how to adjust the handbrake.

Therefore: BEFORE you disassemble and/or adjust everything, first check whether the handbrake is not already loose. To do this, remove the gill plate so that you can look at the brake drums from above. The plate is only secured at the front with an M6 screw.
If the brake band is loose, so that you can move it back and forth a little with your screwdriver, the handbrake is not to blame...

Ok, I was in danger of getting ahead of myself there haha, I really appreciate the advice and hopefully I can get to the root of the problem.

 

[Gin77]

Zetor brakes tends to get stuck if they are not used for a longer period of time. Normally it's the brake cylinders getting stuck because of rust.
Zetor brakes have a bad reputation, but I think it's a bit unfair. The brakes actually work great, if the tractor is being used frequently.

I'm enjoying learning about a tractor, I remember the brakes locking before from over heating but we left it cool down and the were good again.

 

[Joachim]

1. Check the handbrake band adjustment on both sides
2. Open the bleeder nipple, if brake fluid comes out under pressure, then go to 3.
3. Check the brake pedal adjustment for the necessary and important play between the pedal pushrods and the brake cylinders and correct if necessary, then do a brake test and if problems occur again then open the bleeder nipples again, fluid comes out under pressure again, then go to 4.
4. Check the two brake line hoses from the master brake cylinders to the brake pressure compensator. If DOT 4 brake fluid was used, these can swell on the inside, then brake fluid still goes to the cylinders under pressure but no longer goes back into the brake fluid reservoir well or not at all.
5. Replace hoses with new ones and be careful not to mix up left and right! Bleed the system and do another brake test.
6. If it's still not OK, then remove and disassemble/clean the brake pressure compensator and check that it works properly. Bleed the system and test the brakes again.
7. If it's still not OK, you will have to remove one or both portals to get to the bottom of the respective brake system in the brake drum. The wheel brake cylinders can become solid if they are used too rarely and especially if they were installed incorrectly (e.g. if no brake cylinder paste was used).
   

Then put everything back together, bleed it and then the foot brake should work again.

 

[Gin77]

1. Check the handbrake band adjustment on both sides
2. Open the bleeder nipple, if brake fluid comes out under pressure, then go to 3.
3. Check the brake pedal adjustment for the necessary and important play between the pedal pushrods and the brake cylinders and correct if necessary, then do a brake test and if problems occur again then open the bleeder nipples again, fluid comes out under pressure again, then go to 4.
4. Check the two brake line hoses from the master brake cylinders to the brake pressure compensator. If DOT 4 brake fluid was used, these can swell on the inside, then brake fluid still goes to the cylinders under pressure but no longer goes back into the brake fluid reservoir well or not at all.
5. Replace hoses with new ones and be careful not to mix up left and right! Bleed the system and do another brake test.
6. If it's still not OK, then remove and disassemble/clean the brake pressure compensator and check that it works properly. Bleed the system and test the brakes again.
7. If it's still not OK, you will have to remove one or both portals to get to the bottom of the respective brake system in the brake drum. The wheel brake cylinders can become solid if they are used too rarely and especially if they were installed incorrectly (e.g. if no brake cylinder paste was used).

Then put everything back together, bleed it and then the foot brake should work again.

Thank you, I will keep you posted

 

[AntoPro2576]

You could also take apart the half axle. Had to do it with mine and fit new brake shoes as they were seized