Clutch fluid change?

[JB21]

Is there a how to on here for changing the clutch fluid?

My bite has got really low and its struggling to go into gear. Clutch fluid is black so will try changing it to see if it helps.

Also can you only use DOT3 as per the cap instructions?

[Carolyn]

I'm not aware of a 'how to'..

However it's as simple as a hydraulic system can get. There's a bleed nipple on the slave cylinder, with a little help from someone to push the pedal, it's just like bleeding a brake. If you have a vacuum tool, you can do the job solo, and the tool will take all the fluid out quite effectively.
As it's not a braking system and not likely to get hot, I should think Dot 3 or Dot 4 will do the job. I'm not sure the rubber bit would like anything more exotic.

[AdamR28]

As above - did mine yesterday. Open nipple, push pedal down slowly, close nipple, release slowly.

Worth sucking 90% of the old stuff out with a syringe first (leave a bit in the bottom so you don't let any air in!).

DOT4 is also fine. 5.1 (not 5) would also be fine. The higher the DOT number the higher the boiling point, but the faster it takes on water, so no need for fancy stuff for a clutch.

[househead]

I've been planning to do mine soon (and grease the clutch fork as mine is a bit squeaky on and off).

Sounds pretty simple as Carolyn points out. I did find this short guide from searching the forum...

https://www.mr2roc.org/forum/index.php?topic=29469.msg384427#msg384427

[Bossworld]

It's possibly worth replacing/renewing the slave while you're at it, they're cheap enough and when I dismantled the old one to have a look, it wasn't pretty inside.

I got all the fluid out of mine and cleared the master, so was a bit of a fight to get fluid back down again instead of air, but a lot of pumping the pedal by hand (and leaving it overnight) seemed to help

[JB21]

Thanks for the replies. Also read you need to manually pump the slave cylinder by hand to remove the old fluid from it?

[AdamR28]

Hadn't thought of that, but sounds like a good idea!

[Bossworld]

Thanks for the replies. Also read you need to manually pump the slave cylinder by hand to remove the old fluid from it?

Pushing it back/forth (with the nipple open) may get the dregs but would there be any risk sending crap up the line or disturbing 14+ year old seals?   If you're not going to let the system run dry then yeah you might as well have at it with the nipple open.  The one nice thing you should find is that the nipple itself is far less likely to be stuck or rounded, than the equivalents on the brakes.

The colour of the fluid in the frunk wasn't great, and as I say, when I dismantled the old slave out of interest, it wasn't great inside either.  Like Carolyn says it's a simple system, it really doesn't hold much fluid either, just the length of the line increases it I suppose.

I think I paid £7 for a new slave from Amazon but even at full price they're less than £25.  I tend to preach making do and not changing things for the sake of it but if you're only going to do the job once...

EDIT: I found my post and pics

https://www.mr2roc.org/forum/index.php?msg=815960

[Dev]

I would only use DOT3 for a vehicle that says DOT 3 only.  There is a good reason for this as the devil is in the details.  DOT 4 is a different formulation and viscosity. It also has different properties to how it reacts with the absorption of water.  DOT 3 is more hygroscopic than DOT 4 which means it is more susceptible to absorbing more moisture in the air which might seem bad but in actuality DOT 4 is far more water sensitive which will lower its performance and fall off dramatically.  This is why DOT 4 or other high performance fluid needs to be changed more often.  I used the DOT 4 and DOT 5.1 and it doesn't hold up to regular street use and in the cold it was giving me wooden pedal feel due to the higher viscosity of the DOT 4. For my clutch if left in for a year it would create grinding of my gears because of poor disengagement as my pressure plate is much stiffer compared to stock. Once refreshed it would return to normal and that is how I know the fluid was falling me for general street use. 

I have debated this more times than I can remember and if you look on some other Toyota applications they will say either DOT 3 only on the cap or DOT 3 and DOT4.  My Honda lists both but not my MR-S. 
Also the formulation of the Toyota DOT 3 is known to contain a special lubricant which created a recall on certain Toyota cars which used alternative fluids that caused damaged to the rubber in the MC.   
It is not known if the lack of  lubricant in the formulation would impact our systems but there is a lot of other things in the formulation that we do not know about that was specifically designed around our hydraulics.
        Since switching to Toyota DOT 3 fluid I never had any issues what so ever and have great pedal feel. If your car sees a tack and you experience fade only then would I consider spending money on the exotic stuff but not before that happens.

[AdamR28]

Bizarre. I'll report back if / when mine fails!

[Dev]

Bizarre. I'll report back if / when mine fails!

 Just keep in mind that your experience with DOT 4 might not be as noticeable as mine or maybe no issue for the service interval when you change your fluid. I have a kevlar clutch which requires more effort to disengage than stock so in essence the demands of the fluid are probably more and that is why older DOT 4 fluid gives up in less than a year. 
What I am getting at is DOT 4 and DOT 5.1 is a waste of money and will not improve the clutch and in cases like mine will not last as long for street use once it takes in a little water.  DOT3 although takes in more water is resistant to the exponential drop off. 
 
Also Toyota brake fluid is not exactly typical DOT 3 fluid. Oddly enough it has been widely reported that its  formulation uses a  Borate Ester and it is believed that is what differentiates DOT4 from DOT3 so it might be a low viscosity DOT4 but that is just speculation on my part. There might be other unknowns in the formulation that is important for seal longevity and cold weather performance for ABS operation.  These little details may not be fully realized in the short run but it might create issues with earlier component failure in the slave or master compared to a system that has used only Toyota brake fluid.   

[Petrus]

There might be other unknowns in the formulation that is important for seal longevity and cold weather performance for ABS operation. 

Hmmmm...
Maybe delete the ABS then after all and enjoy another weight saving :-)

[JB21]

Just ordered ATE DOT 3 fluid from ECP. When the car is cold it goes into gear fine, the hotter it gets the harder it is to go into gear. Hope the flush solves the issue.

[thetyrant]

Just ordered ATE DOT 3 fluid from ECP. When the car is cold it goes into gear fine, the hotter it gets the harder it is to go into gear. Hope the flush solves the issue.

What gear oil have you got in ?

[JB21]

Just ordered ATE DOT 3 fluid from ECP. When the car is cold it goes into gear fine, the hotter it gets the harder it is to go into gear. Hope the flush solves the issue.

What gear oil have you got in ?

Redline MT90

Forgot to mention the clutch bite has lowered to an inch off the floor making me think its the hydraulic system.

[thetyrant]

Yes does sound like it so will be interesting to see how changing fluid alters things, fingers crossed it sorts the issue for you

Did you put a new clutch in when you changed the engine ?

[JB21]

Yes does sound like it so will be interesting to see how changing fluid alters things, fingers crossed it sorts the issue for you

Did you put a new clutch in when you changed the engine ?

New competition clutch and lightweight flywheel fitted in the rougue build 2k miles before the bottom end went so just refitted them.

[Dev]

Just ordered ATE DOT 3 fluid from ECP. When the car is cold it goes into gear fine, the hotter it gets the harder it is to go into gear. Hope the flush solves the issue.

 That is exactly what I experienced with old DOT4 or even DOT5.1 once everything heated up. I know it was the heat because I would shut down and let it sit for a half hour and it would engage the gears again without grinding just enough to get me home. I would flush it with fresh DOT4 and everything was fine for 6 months until it would act up again in the same manner. I did this dance for two years until I switched to Toyota DOT3 and I never had an issue. 

[JB21]

Clutch fluid changed and zero difference. Then remembered that you can alter the clutch bite under the pedal with the little rod thing. 2 turns clockwise brought the pedal up an inch or so and BOOM! All sorted.

Lovely precise changes now. Must have been dragging ever so slightly for ages as I've always had an issue engaging 5th, not now.

[thetyrant]

Nice job , just make sure there is still some freeplay on the pedal before it starts to move cylinder, many people make the mistake of removing it all on both clutch and brake pedals to get them as sharp as possible, however it then doesnt leave room for expansion and causes all sorts of issues!

There will be a spec for amount of freeplay in pedal somewhere in manuals will see if i can find it.

[thetyrant]

Heres a picture i found online for clutch pedal adjustment on the mk3

[househead]

Heres a picture i found online for clutch pedal adjustment on the mk3

I was just about to post this document which has the clutch pedal spec, but you already covered that.

It's such a useful doc though, I'm going to post it (again) anyway...

note: this is for FL.

You cannot view this attachment.

[Ardent]

everyday is a school day.
Never seen that before. Saved. Filed. Stored.

[JB21]

Nice job , just make sure there is still some freeplay on the pedal before it starts to move cylinder, many people make the mistake of removing it all on both clutch and brake pedals to get them as sharp as possible, however it then doesnt leave room for expansion and causes all sorts of issues!

There will be a spec for amount of freeplay in pedal somewhere in manuals will see if i can find it.

Cheers Ian. Didn't actually check free play, will have a check later. I was just made up I had gears again. Surly if there was no free play in the pedal before you press the clutch down you would feel the car revving like it was slipping?

[thetyrant]

Cheers Ian. Didn't actually check free play, will have a check later. I was just made up I had gears again. Surly if there was no free play in the pedal before you press the clutch down you would feel the car revving like it was slipping?

The free play and the total stroke are important so need to check both once you start adjusting the pedal end, in normal circumstances you should never need to adjust pedal end unless the clutch/flywheel has some differences over stock,as your on uprated both its probably why it needed it a tweak and as long as you have some freeplay you should be ok there but check the stroke as well as you can overpress clutches, if you have made stroke too long it will shorten pressure plate life by stressing springs beyond there design.

From what you have said i think you will be ok but ive seen people adjust too much and have either clutch right on edge of slipping or clutch pressure plate failing due to over pressing it, you want to adjust it as little as possible to allow clutch to operate as it should but as you can see in above pic there is quite a wide tolerance so 2 turns should be fine but best to check as might save you changing clutch