Brake Fade Zetor 5245

[smokysun]

Hello, my 5245 has just started having brake fade after I take my foot from the pedal, and it sets for more than a few seconds.
It was not doing this last week.

Yet, I can pump it up if I do so fast. And hold it without the brake fading.

I can hear a very, very faint hiss type sound when I release the pedal. Yet I do not see any bubbles coming up into the reservoir.

The tractor has 1180 actual hours on it. And is currently wearing an Allied loader, which has its controls mounted on the master cylinder side of the tractor. So given the tractor is outside, and I have no garage in which to work, I don't want to take things apart in a guess to try to figure out what is wrong.

Any thoughts as to what it could be? I did check the lines going to the fluid reservoir, and they are not leaking.

Also, the clutch side has a notice to lubricate every 100 hours.
But, it does not say exactly where, and with what?

I would appreciate any thoughts. And recommendations where to get parts. Especially seals that do not crumble, such as those above the transmission on the shifting levers. Any makers of silicone seals?

Thank you.

Smoky

 

[ixer0]

Hi

By brake fade I guess you mean the pedals are going to the floor with no resistance ? If you're not losing fluid you will need to replace the master cylinders. A temporary cure may be to try bleeding them and see how long they last.
The lubrication sticker is for a squirt of oil down the pipe through the clutch inspection cover to lubricate the thrust bearing carrier.

Mike

 

[smokysun]

Hi Mike,

Thanks for the reply.

I found the brake fluid return line had a pinhole right under the fluid reservoir, and it had slowly leaked enough fluid so it did indeed suck some air into the brake cylinders. I also found that one needs 12 inch long fingers, with 8 on each hand, and 9 wrist type joints on your 3 foot long arms to reach the bleed screws.

And more importantly and seriously, a 9mm open hex wrench with a 70 degree bend in it just above the actual wrench head, to bleed the brake cylinders. That I had to make from a standard wrench.

Those buggers are in tight spots. When it warms up, I am going to remove the bleed tubes, and replace them with ones with tubes about 3 times as long with the hex more elevated
so it will be much easier to bleed them then. I wonder if those tubes are made, or will I have to make them? I will find out.

I also am glad I thought of tying a nylon string tightly to the wrench, and securing it around my wrist in case I dropped it, given how tight it was in the axle house. Because I would have dropped it about 20 times. Especially since it was about 18 degrees out, and I could not get in there wearing gloves. I hate to think what it would have taken to remove it.

There was lots of air in the cylinders, but, once bled, the brakes now work fine. Later today, I am going to do the clutch cylinder, as it was not shifting all that great today, so some air must be in that cylinder, too. That is going to be a lot easier, and seeing how the fluid looked from the brakes, needs to be done anyway. I just needed to use the tractor to pull some people's cars and trucks from ditches today.

We are WAY above normal on snow here in southern Ohio, and way below for temps. Our local highs are about where our lows should be, and the weather forecasters are giving high odds on another major storm for this weekend. One odd winter. I will be glad to have a working tractor.

I purchased the service manual for the tractor. Not the greatest in illustration or description if you do not have one, and were thinking of getting it. Almost an assortment of garage mechanics descriptions and illustrations.

I have found one source so far, for replacement cylinders, but not rebuild kits for them. Are such even made?

Anyway, thank you again for replying. Lets hope for an early spring, eh?

Best regards,

Smoky

 

[ixer0]

Hi Smokey

These are a mans tractor and not for boys !!! They get easier the more you work on them, I'm on them all day every day. The genuine Zetor bleed spanner is the 9mm box spanner about 3" long with a tee handle across the top.
We've had an unusually bad winter her in the UK too. Global warming -- pah, global b****y freezing more like.
The seals for your cylinders are available from your Zetor dealer but it will usually only be a temporary cure as the cylinders wear and rust. My advice would be change the cylinder complete if you get problems, they're not too expensive.

Mike