'94 C50 master cylinder or hydraulic leak?

[Sven]

Hi guys,

So it seems the Corolla has a hydraulic clutch, and there's a good chance I don't have enough fluid in there to pull the clutch plates apart, but here's what happened so maybe you could diagnose more accurately:

I drove home fine last night from oakville to London (~150km), everything's cool - even getting off the highway and coming to a few sets of lights on the way home.

Then I pull into the parking garage and pass my spot, ready to back in. Pushed the clutch down, put it in reverse and the car kinda started backing up before I took my foot off the pedal.

I push my foot down even harder and pull the shifter into neutral. Then I tried putting it into reverse again and it kinda ground the gears a bit and started going back already. Same with 1st gear - they just grind as if I didn't have the pedal down. I ended up turning the engine off and pulling/pushing my car into the parking space.

Seems like the service girl at a Toyota dealer here didn't really know what I was talking about or something cuz she started staying it's the same fluid as for the brakes... I couldn't understand that part at all.

Any idea what this would be, or how much it would cost? The clutch doesn't slip at all but because of this problem the pedal does feel noticeably squishy and lighter, though there is still some feel to it.

[94_Rolla_Guy]

Yes the clutch will be a hydraulic theres the clutch master (on the firewall right behind the drivers shock tower) then theres the slave Cylinder on the front of the transmission right where it joins to the engine

The girl at toyota is right the hydraulic system uses DOT3 brake fluid as the hydraulic fluid.

Now more than likely the problem is the slave cylinder there always the first thing to go!
squeeze the rubber boot and or take it off the housing if you get fluid then its shot, also check the master under the dash see if its wet or dripping

Some parts stores offer a rebuild kit which ive been driving on for 2 years or you can just get a replacement part for a bit more..


If you do change it you will have to bleed the air out this is done by filling the resivour then having someone push the clutch down then open the bleeder screw the pedal will get soft then repeat keeping the resivour topped off

[Sven]

Hmmm k thanks man I'll check the slave cyl. when I get home from work.

Toyota girl though was giving me the impression that I would notice something strange in the braking system if the hydraulic clutch was going (i.e. they use the same system) which didn't make any sense to me whatsoever, but it does make sense they'd use the same fluid.

If I could get the slave cylinder part, is there a relatively easy way to install it myself? I have a limited aray of tools and the standard car jack.

The only problem is that I live in an apartment building that frowns on any type of do-it-yourself repairs on the premises, though I might be able to do it in a friend's driveway of his house.

I'm assuming though that I'll just head to a local shop to get it done.

[punter]

Originally Posted by Sven

Toyota girl though was giving me the impression that I would notice something strange in the braking system if the hydraulic clutch was going (i.e. they use the same system) which didn't make any sense to me whatsoever, but it does make sense they'd use the same fluid.

Some cars do share one resiovoir between the brakes and clutch, Just have a look on the engine side of the firewall, Above the pedals, Do you see 2 little tanks or 1.

[94_Rolla_Guy]

on 93 - 97's the clutch and brakes are completely seperate!

[Sven]

So I had to get it towed away this morning, they replaced both the master cylinder (leaking) and slave cylinder (possible area of previous leakage though it was dry at the time).

The one thing I noticed now though is it seems like the clutch is taking up much later in the travel (i.e. the last 3 inches) where I think it was picking up closer to the floor before.

Any ideas why this would be happening? All in all it does feel tighter now but feels like I'm driving another car.

[toyotaspeed90]

Originally Posted by punter

Some cars do share one resiovoir between the brakes and clutch, Just have a look on the engine side of the firewall, Above the pedals, Do you see 2 little tanks or 1.

i have never seen a car that shared hydraulic reservoirs..... and in fact, i'm gonna have to say you're down right wrong. Why? because the way hydraulics works is if you push in the clutch, then you would also be putting pressure through the brake system... thus everytime you push in the clutch, the car brakes... and every time you brake, the clutch goes in..... the only way it COULD work is if you have a large reservoir above both the clutch and master cylinders, and each has a 2 way check valve..... but that's 100X harder than adding another reservoir tank


the slave cylinder (especially on FWD corollas) is VERY easy to swap out... hardest part is bleeding the system (and if you know how to bleed brakes you're set...). There is a hydraulic line (10mm... make sure you get a flare nut end wrench...... otherwise there's a high chance of stripping the nut... then you get to learn how to cut then flare a hardline) that leads into the slave cylinder. Remove it, and slightly bend the line back away from the slave cylinder. There are 2 bolts that hold the slave cylinder onto the tranny (12mm or 14mm... cant' remember). Unbolt them and the slave cylinder is off in your hands.

the master cylinder is a bit tougher.... first thing i would do is check (just because i'm a pessimist) to see if fluid is coming backwards into the cab.... older toyotas used cast iron slave cylinders... which after time pitted from the hydraulic oil & pressure.... and when you push in the clutch, the plunger passes by some fluid... release the clutch and the fluid comes backwards into the cab..... Later toyota got smart and used aluminum master cylinders which don't pit.... strangely they fixed this problem in 88 in mr2's.... but i know my 90 corolla has a cast iron slave cylinder. To replace that you have to remove the clutch line, then crawl inside the car and disconnect the arm from the pedal (there's just a hairpin holding another pin in... it's quite simple once you get in). Then unbolt the 2 bolts from the master cylinder & pull it out. Reinstall is a bit tougher since you're supposed to bench bleed a master cylinder... (not required in a slave)

[Sven]

Thanks toyotaspeed90, I had to just take it in this time but once I move back to a proper house where I have all my tools I'll be more apt to fix stuff like this myself.

Regarding the clutch takeup

The mechanic said he set it back to what it was when the car came in, so maybe over time, my slow hydraulic fluid loss was making clutch takeup closer and closer to the floor?

Correct me if I'm wrong, but I suppose the further in the pedal travel the clutch takes up the further away the actual plates part themselves when I push the pedal down?

I.e. having it take up right off the floor could mean when I push the pedal all the way down that they're seperating just barely enough to disengage the power - which isn't good, but I'm sure there's a happy medium somewhere.

[punter]

Originally Posted by toyotaspeed90

i have never seen a car that shared hydraulic reservoirs..... and in fact, i'm gonna have to say you're down right wrong. Why? because the way hydraulics works is if you push in the clutch, then you would also be putting pressure through the brake system... thus everytime you push in the clutch, the car brakes... and every time you brake, the clutch goes in..... the only way it COULD work is if you have a large reservoir above both the clutch and master cylinders, and each has a 2 way check valve..... but that's 100X harder than adding another reservoir tank

Huh what are you talking about, obviously you haven't work on many older japanese cars.

The way it works is you still have a seperate brake and clutch master cylinder but the both share the same reservoir.

Since the reservoir is never pressurised this causes no problem.