Valtra Slave Cylinder

[N1ck]

After replacing both master cylinders on my Valtra 6300 within the last 12 months I think I have finally traced the persistent loss of brake fluid to the left hand slave cylinder. It's really hard to see as it is buried under the cab under a load of hydraulic hoses and caked in crud.

 

Has anyone got any experience of replacing the slave cylinder on a Valtra and can give me any tips?

 

Should I replace both slave cylinders while I am at it, the right hand one looks even harder to get at and at £130 a pop for a genuine Valtra part I would prefer not to.

 

Are the seal kits worth it or do I just buy a new cylinder? When I replaced the master cylinders I asked my Valtra dealer about the seal kits (which weren't a lot cheaper than a whole new cylinder) and was advised not to bother but then they would say that.

 

Do people still use DOT4 in the brake system as recommended by Valtra or has anyone switched to mineral oil?

 

Cheers

[MrNick]

Whatever you do don't inter change dot fluids and mineral fluid The seals of the system will not like it, use a higher spec dot

[openspaceman]

After replacing both master cylinders on my Valtra 6300 within the last 12 months I think I have finally traced the persistent loss of brake fluid to the left hand slave cylinder.

 

For future reference : master cylinders seldom fail leaking fluid as it just goes back to the reservoir and the rod seal isn't under pressure, so if the fluid level is going down it is most likely to be a slave.

 

I've not experienced Valtra's other than driving one.

 

 

Do people still use DOT4 in the brake system as recommended by Valtra or has anyone switched to mineral oil?

 

Cheers

 

Whatever you do don't inter change dot fluids and mineral fluid The seals of the system will not like it, use a higher spec dot

 

Take heed of what Nick says, someone put brake fluid in our JCB telehandler and it caused the seals to leak and this was one case where the master cylinder was remote from the reservoir and did escape, £900 for the part and no seal kits available.

[N1ck]

There was a slight leak from the master cylinders leading to fluid weeping out behind the console in the cab but this obviously wasn't the main problem.

 

I have stuck to DOT fluid but I am starting to worry what effect it is having, corrosion wise, on the back end of my tractor.

[openspaceman]

There was a slight leak from the master cylinders leading to fluid weeping out behind the console in the cab but this obviously wasn't the main problem.

 

Yes this would be typical of failed seals but it's only a weep because the seal on the rod isn't pressurised.

 

I have stuck to DOT fluid but I am starting to worry what effect it is having, corrosion wise, on the back end of my tractor.

 

There are various DOT fluids, some are poly ethylene glycol based with organic copper compounds and others silicone based, not at all similar to the mineral oil that the back axle or hydraulics use. I'm certain the glycol ones will damage seals meant for mineral oils.

[N1ck]

I'm using DOT4. I'm more worried about the effect on the paintwork / metalwork at the back of the tractor than the seals, although everything is coated in a film of hydraulic oil from a leaky valve chest so that is probably quite an effective barrier.

[lornah1979]

Give Paul Whalen a phone at Jas p Wilsons in dalbeattie - he might be able to give some advice - excellent Valtra mechanic

[Logan]

Hi N1ck,

 

I've changed them on a valtra 6550 hi-tech (with the parking brake up on the for-rev shuttle by the steering wheel), is yours like this or do you have a separate handbrake?

 

Looks bad, but once you get used to the small space under the cab they come out ok. You may want to clean it off under the back to make it easier for yourself.

 

You have to release the parking brake and clean/lube the mechanism up by the slaves (cable ends and swivels) while doing. Then you can work on undoing the brake lines with a decent brake line spanner. The brake lines look healthy? If not, now is the time to change them.

 

Then you can unbolt the slaves.

 

Once back together, you'll need to bleed them obviously (dot 4) then go through procedure for adjusting brakes, then adjust handbrake mechanism last. The operators manual covers this very well, if you have it.

 

Replace both, the side that isn't obviously leaking now will be once you changed the other. Get new slaves.

 

May need to loosen one of the quick release spool fittings to get spanner room, you'll see.

 

Cheers, John.

Edited May 5, 2017 by Logan
slow brain function

[s o c]

Brakes on my 6400 are barely working since last couple of hours of last job before holidays.

not losing fluid, left pedal goes straight to the floor, right pedal poor but not as bad. 
do both slave cylinders usually fail at same time? Seems to have gotten bad all of a sudden .

today was the first chance I had to take a look, the only thing I could notice was that flexible pipes from reservoir to both slave cylinders look kinked and collapsed.

Any theories?

 Thanks 

[woody paul]

When you push the pedal dose the fluid level in reservoir raise or stay the same.