Very weak brakes on a 5711

[sveinha]

Hi all

I have today bought a 1978 Zetor 5711 unseen. The only thing that doesn't work is the rear brakes, they are very weak or not working at all. It will take a week or so before I receive the tractor (need to arrange about 700km transportation) and in the mean time I hope to get an idea of what work is needed to repair the brakes. The parking brake is very good so I assume this is separate from main brake with its own shoes?

According to the previous owner, spare parts is cheap but it involves a lot of work to repair.

Anyone who can give a short description of what most likely have to be done? Any special tools needed?

 

[grumpy6711]

yes parking brake and foot brake are separate. parking (hand) brake is cable operated and 'pulls' steel bands around drum to stop.
foot brake hydraulic - consists of pedal - master cylinder - brake line - wheel cylinder - brake shoes.
to change wheel cylinders or brake shoes rear axle housing must be removed. very heavy! i have sent you a private message with a link to something you may find helpful.
good luck

 

[sveinha]

Thanks grumpy

Anyone having a hunch what may be the problem? The most commen causes of weak brakes on Zetor ?

 

[Renze]

rusted slave cylinders, stuck shoe pivots, metal to metal contact (brake shoe lining worn clean off)

 

[sveinha]

Thanks, I'll let you know what I find, probably some time during next week.

 

[Renze]

I'm going to do my brothers 6718 tomorrow...

Make sure you have a lifting device that reaches under the mudguards, to lift the end reduction housings off it.
I bought one of these, purposedly for brake jobs: https://www.powerplustools.nl/

This adress asks 299 euro, but i got exactly the same Chinese made workshop lift for 115 euro..

 

[Renze]

Oh, doing the brakes today i thought i should give one more thing to watch for:

I have never seen a worn brake shoe on a Zetor ... they all stopped functioning because the cylinders were rusted or the pivot points seized.

I filed the side faces smooth, sandpapered the pins, and sandpapered the pin holes in the brake shoes untill the pins have a loose fit: they are held with strong springs (use a piece of wire to pull them on: when attached, cut the wire and pull it off) so the loose fit will never make them rattle.
Therefor, file and sandpaper till they fit very loose ! that prevents future seizing.

Then smear good amounts of copper compound, graphite grease or other heat resistant anti-seize lubricant on the pin and mating surfaces before assembly.

 

[sren]

Hei,
I had the same problem, bought a unseen Tractor (6245) with weak brakes. The cylinder was the problem, it was leaking. With some help from the Forumpeople it was not so difficult. But the parts are heavy, I used a crane to lift it. I damaged the pipe when I tried to open the screw to the cylinder, so be careful with that, Good luck Sren

 

[sveinha]

Thanks Sren.

It seems like a pretty straight forward job but handling of the portal requires some kind of a crane. Ordered the nessesary parts today. The previous owner have changed the master cylinder so I hope that one is Ok. There are a hole in the hose from the brake fluid tank so there might have come some water in the master cylinder, time will show...

 

[rajiv_ahuja]

A cheaper tool is the Chain pulley Block. Make a tripod using old hollow pipes with a bolt on top.

The Differential Shaft has to fit into the Sun Wheel else the Crown Oilseal will get damaged.

Also, after fitting the Wheel Cylinder, Brake Shoe and Springs and Pipe, remember to bleed the brake system for air pockets, else the brakes will not engage.

Keep a cloth under the Bleeding Nipple of the Wheel Cylinder to prevent Brake Oil from leaking onto the Brake Shoes.

 

[Renze]

A cheaper tool is the Chain pulley Block. Make a tripod using old hollow pipes with a bolt on top.

Its cheaper, but requires taking the mudguard or cab off... On an open tractor it will work, parking it under a shade tree with a pulley on a branch, but on cabbed tractors its a pain in the ass, to work under the cab...

 

[sveinha]

I was originally planning to park under a roof and use some lifting device from the roof but I see that mudguards and other things need to be removed. This crane may be useful

Verkstedkran, 1000 kg

Hydraulisk kran for å løfte motorer. Med vribar løftekrok og uttrekkbar løftearm for 4 alternative løfteposisjoner med ulik maks.belastning. 6 hjul, hvorav 2 er svingbare. Sammenleggbar for enklere oppbevaring. Løftekapasitet / lengde på løftearm 250 kg: 1250 mm 500 kg...

www.biltema.no

Similar to the one Renze linked to. Lifing up to 2000 kg and cost NOK 2000 which is something like EURO 250

Think I will get started on the brakejob within a few days. All parts have arrived...

 

[carrick]

I made a plate which slots on to trolly jack head with 2 upright bars which fit snugly arround the half axle in the groves for bolting stabilizers to and this safely removes half axle on larger zetor model. Sure somthing similar could be made for smaller model.

 

[sveinha]

Started the job yesterday evening. After slightly more than one hour, I needed the crane (bought the one I linked to) and started unpacking it. Lots of parts were missing, there have to be two boxes and I only got one... All bolts, wheels and some other parts were missing...

So far, it seems to be a fairly straight forward job but I managed to break off the brake pipe when disconnecting it

 

[Renze]

I have all parts for a brake job on the 5511, but i will order new brake pipes first, because breaking the brake pipe is what i do 3 out of 4 times...
You paid 250 euro, only the colour is blue instead of red like mine... it seems i DID get a steal deal on it
I checked lately but the wholesaler i bought it, stopped selling this line of chinese tools, to i think i got a special clearance price

 

[sveinha]

The crane took the better part of an hour to assemble and is very useful for the brake job.

Got it all apart yesterday. Lots of cleaning to be done today.

I think I have used about 2.5 hours so far. Were struggeling a bit with the bracket for the cabin until I found out that I had to remove the bolts on both sides of the cabin and lifting it about 5 cm.

I still think this is a fairly straight forward job but when handling heavy equipment, things take time...

 

[sveinha]

One side ready for cleaning...

When lifting the cabin a few cm, the bracket on the other side was easy to remove. I'm considering to remove the inner side of the U-profile because that is the one that causes problems and I don't see what use there is for it. The cabin is quite a bit smaller than the U and therefore there are shims between the U and cabin.

 

[Renze]

5711 with cab, so its not a Zetor cab... What cab is it, Hara ?

 

[sveinha]

I have no clue which cab it is but it looks great.

 

[forterra9641]

i think its a original zetor cab renze. they were sold here in norway because of the cold climate we have with these cabs wich i believe is of zetors own production.

 

[sveinha]

If the cab was delivered with the tractor from the factory, the model number should be something like 5718? The nameplate states 5711c. Found this nameplate on the cab.

 

[forterra9641]

Thats the nameplate of an original zetor cab. the type is BK 6718.

 

[Renze]

It does look a bit like the 4718 cab, the narrow type. On the 6718 of my brother (and i think also our old 5718, now long gone) had the cab mounted in rubber bushings, not with two bolts on each side, through the cab frame.

 

[sveinha]

The rear wall/window is home-made by previous owner but looks great. I would believe it was original unless told otherwise...

The brake problem was leaking slave cylinder. In the brake house, I dug out almost 1/2 litre of various sludge from brake fluid, oil , leafs and a couple of spruce cones...

Changed the seal to the gearbox as well. The original seal was a zimmerring 58-80-13 which my local shop didn't have in stock so I put in two 58-80-8.

I used about 4 hours to do one side but so far I haven't connected the brake pipe. As long as the nut on the brake pipe is as long as about 5-6 cm it is virtually impossible to loosen them without destroying the pipe. Had to drill out the rest of the pipe from the nut.

Doing the other side during the week and the hydraulics when finished with the slave cylinders.

 

[sveinha]

Brake job finished. It all took about 12-13 hours but now ALL brake parts are brand new

Needed new copper washers on the bolts on the outlet side of the master cylinders as it obviously is not 100% aligned. The old washers were slightly misformed and didn't seal at all. Anyone who knows what the cylindrical unit on the outlet of the master cylinders are?

I may believe it to be some kind of pressure equalizer for balancing the brakes when using both brakes simultaneously?

Both brake pedals springs a good deal as if there is air in the system but I have bled a lot and there are no more air now. Is this normal or should the pedals stop in one more or less fixed position?

 

[alan]

Yes it is a pressure equilizer

 

[dave_peters]

You are right, its a brake balancer, inside is a shuttle valve that stays central when both pedals are pressed, but moves when only one is pressed

 

[grumpy6711]

my brakes are not the best in the world and have only one tractor for experience but if i split the pedals and use either one there is quite a bit of pedal travel, but when pressed together hardly any travel at all.
so i guess thats the equaliser working as it should?

there seems to be something else missing from your tractor Svein - lots of rust and dirt

 

[sveinha]

You're absolutely right, Grumpy, very little rust and dirt. Previous owner did a good job with the renovation of the tractor. He bought it more or less like a wreck 7-8 years ago.

I think I have to use very much power on the brake pedal and think it's a bit strange compared to the hand brake which is exceptionally good. Different technology but they share the same brake drum...

 

[forterra9641]

you say thath you have to use very much power on the pedal..... did you change the brake shoes when you had it apart ? if not and the old liners were soaked in oil and brakefluid, even if you wiped them. the shoes may be slipping inside the drum. when this assy is dry and new you should not have to use much force on the pedal. also a thougt is that the seals where damaged during reassembly. or that the fix with two simmerings is not functioning.