Clutch Hydraulics Diagnosis

[BarnOwl]

This one comes up enough that I'm going to get it made into a How-To.

Symtoms

The car is hard to shift especially into 1st or reverse while running but, will shift smoothly with the engine off.

Quick Tests

On a level surface, with the engine running, hold the clutch in for a minute or two. If the car starts to creep forward after waiting a bit, it's a good indication that the problem's hydraulics. If it starts to creep right away, it could be another problem.

When the car is hard to shift, try pumping the clutch a few times. If it gets easier to shift, it's probably a hydraulic problem. If not, you really don't know.

While the above tests will give you a pretty good idea what's going, on they are hardly definitive. Given that the price of a clutch hydraulic assembly is more that $100, you really want to be right when you buy one.

The Definitive Test

First check the clutch pedal travel as shown in the picture below. It needs to be 135 mm to 156 mm (5.3 - 6.2 in). If it isn't, there's some obstruction or the dash is damaged.



If the pedal travel checks out, there's a small access hole next to the slave cylinder (see pic below). Stick a piece of stiff wire in that hole till it touches the fork and mark the wire where it goes into the hole. Do the same thing with the clutch pushed all the way in. The distance between the marks should not be less than 11.18 mm (0.44 in). If the distance is too small, it's the hydraulics. Otherwise, your looking at a damaged fork or pressure plate.

[Greg1]

Well done!

[MikeNW]

Great article!
One question I have, is I measured my clutch pedal travel at 5-1/4 inches. There is no way to make it greater. Unless you cut out part of the factory carpeting. I wish it was greater! no obvious damage to an parts or mechanisms.

[kurtr]

If you are confused, as I was, as to where this access hole is near the slave cylinder, read on.

Here is a picture of the thing you are looking for: http://www.saturnfans.com/photos/sho...hp/photo/44240

You'll see it looking from above sort of near/under the battery. You can also get a good look at it by looking in from the side. Look from just in front of the driver's side front tire. Only from this position could I see the access hole.

[shae marks]

Clutch Hydraulic Diagnosis

If you suspect a hydraulic problem with your clutch, bleed the system. This may take some time and a lot of fluid to insure that all air is out of the system. The most likely cause of fluid loss or air in the system is a bad seal in the clutch cylinders. Most time it is the Slave and it is the cheaper of the two repair and replace. So if you are guessing side with the cheaper. Use only Dot3 brake fluid or Delco Supreme #11 brake fluid. Do not over fill the reservoir. Do not over torque the bleeder screw or hose fittings(only 12ft lb.). Make sure the bleed screw dust cover is in place or water will leak in to the screw and cause rust in the slave cylinder.

[BarnOwl]

Originally Posted by shae marks

If you suspect a hydraulic problem with your clutch, bleed the system. This may take some time and a lot of fluid to insure that all air is out of the system. The most likely cause of fluid loss or air in the system is a bad seal in the clutch cylinders. Most time it is the Slave and it is the cheaper of the two repair and replace. So if you are guessing side with the cheaper. Use only Dot3 brake fluid or Delco Supreme #11 brake fluid. Do not over fill the reservoir. Do not over torque the bleeder screw or hose fittings(only 12ft lb.). Make sure the bleed screw dust cover is in place or water will leak in to the screw and cause rust in the slave cylinder.

Yes but, Saturn clutch hydraulics do not have bleeder screws. Some early models did have a screw for filling at the factory but, most do not. The system is nearly impossible to bleed. There is another post in the How-To library that details about the only way I would try it. It involves dismantling the slave cylinder while keeping the system full...good luck.

[macospro]

Great article, it helped me with my practical!!

[jerrussell1976]

Where exactly is the access hole to the test? I searched and I searched for it and I cannot find it. Does someone have an actual picture that they can point the hole out? I have a 1998 Saturn SL.

[archebald23]

one thing i noticed, i cant find screws for bleeding unlike the ABS Hydraulic Assembly. Dismantling the slave cylinder is too much work, is there an easier more practical way?

[cosmic_kid]

In the quick test, do you hold the clutch in with it in 1st, reverse, or neutral? Do you have to remove the air intake and battery to get the wire into this hole? When looking from the side, are you looking past the tire, and if so, do you have to remove the black plastic shield inside the wheel well? What if it is a damaged fork or pressure plate? thanks, Will

[jamminjames]

Just a tad confused on the The Definitive Test. I did the test on my car, and im comming up with basically double of the 11.18 mm. Is this normal or is something not right here? I know if your under the 11.18 mm your going to have issues, but what if your well above the 11.18 mm?

Thanks

[GorgeGeorg]

I also have a question on the travel distance.
My pedal travels just over 6" which in the proper range.
But my test of the 'clutch fork travel' distance is about 0.55"
which is a little more then the suggested distance. A small
amount of the difference could be measurement error.

How critical is this distance?

[coffeyman11]

Great post, it really helped me! I had a tough time figuring out where the slave cylinder was. I just searched Google images to see a picture. I could get to it from under the car, but it was really tight, so I ended up having to remove the battery and the battery tray. Then it was pretty easy. I used a clothes hanger and I noticed that depending on which way I angled the hanger, it would sink to a different depth. I figured out it was best to have it angled slightly down. I poked it around and had my wife engage/disengage the clutch and I knew I had it when I finally saw the hanger move. Then I took the measurement. All my measurements are fine, so I guess it's my clutch assembly that needs replacing. Thanks again. Good luck to the rest of you.

[dano2201]

Barn Owl, I read your post from 2007 on pedal travel and fork travel for the saturn clutch. I have a 1998 SC1 that I just finished putting a new clutch in. Should have known something was wrong because it went back together too smooth,(except for a seal on the output shaft giving me and $80 headache, cost for the tool to install the seal).
Like many other posts, upon starting the car, I had difficulty shifting gears while engine on, no problem shifting engine off. I did the measurements and I fall right on the .44" on the fork and almost 6'' on the pedal.
While the car is running, and I start to release the clutch pedal, the car starts to move. Like the other posts, its almost immediatly that clutch starts to engage. The slave does not have any leaks when checke for that.
When I first pushed clutch pedal after installation of clutch, pedal felt like there was nothing there, even after pumping on it. I checked the slave reservoir to see that it was low, so I put some brake fluid in it. After that, I went to pump the clutch and it was as hard as a rock. Not knowing what to do next, I removed the slave from the clutch housing and the freakin actuator rod fell into the housing...I almost cried, but remained cool. Got a magnet on a rod and fished around til I felt a "click" and lo and behold there was the rod. I put the rod back in the boot on the slave and guided it into place and re-attached everything. Pressed on the cluch and it seemed better than it was the first time, and at least I could depress it.
Would adding fluid to the system cause the clutch to act that way?
Thanks for any information,
dano

[dude33333]

Thanks for the great article.
I would like to confirm that using your logic, I definetly have a hydraulic problem before I replace the system ($135 for the part at pep-boys).

I have the "symtom"

of the "quick tests" it DOES creep right away. and it is NOT easier to shift after pumping the pedal.

"definitely" I measured about 1/4" movement of the wire when inserted into the hole.
I measured it without a helper, so propped the clutch pedal down and remeasured, not sure if that makes a difference. Also, I forgot to measure the pedal travel, but Ive owned this car for 9+ years and it seems about right, although, the point where I feel a little preasure is way down to where the pedal is almost bottomed out.

So I should replace the hydraulic system right?
THANKS!

[khabibul35]

Too little too late for me since I pulled out the slave cylinder to try to do the wire test (not quite understanding what to do). However, while looking on the internet regarding clutch fork issues I did stumble across this video which shows exactly what the wire test should look like:

http://www.youtube.com/watch?v=099IRHql-qc

Hope this helps someone out.

[khabibul35]

Another item for reference is this pic I found elsewhere on the forum for the recommended clutch pedal travel vs fork travel.

http://i202.photobucket.com/albums/a...ravelgraph.jpg

[radtek]

On my 98 SC2 the wire measurement was .53, is this still within the limits of being ok?