Clutch???

[Steve Demeter]

1990 Citation Pinto FC. Tilton 7 1/4 clutch, Saab annular slave cylinder. Pressure plate just surface ground. New Tilton Disc. Verified stack height on flywheel was same as before new disc and surface grinding. Actually a bit taller since grinding onlt took about 0.005" off.
Replaced slave O Rings. Tested for leaks with bar bolted to bell housing and master hooked up. no leaks (bled it first). Stroke limit set by pushing car in gear while driver gradually moved clutch in until it JUST slipped. Set pedal stop 1/4" past that point. Pushing it around garage and keeping it in gear to keep from rolling worked as usual.

Went to do test drive around block today. Pushed it into driveway, slipped it into gear as driveway is a bit sloped. Installed driver, slipped it into neutral, started engine. Put clutch in and slipped into first and eased out of driveway. There is a dip at the bottom that I always coast over, so put clutch back in there. Pedal felt fine for an instant then went to floor. and all of a sudden no drive. Could shift from one gear to another, clutch pedal dropped right to floor.

Got it back into garage, and there was a big puddle of brake fluid on the diffuser, but it was all at the front, none anywhere near bell housing. Looked closer and found that line had gotten pinched and that was where the leak was from.

Removed bad line. Confirmed failure.

Tried blowing compressed air into slave cylinder via fitting that line connected to on bell housing and rubber tipped air nozzle. It appeared that no air was escaping.

Thought might had had a cv joint failure jacked rear wheels up and checked all 4 and they all still turn the halfshaft.

next thing to try tomorrow is to remove box rear cover and verify that the pinion shaft is connected to the rear wheels by trying to turn it with the wheels on the ground. with box in neutral Should not turn.

Then going to try same thing with layshaft with box in neutral also.

If all of these check out I am lost. I am suspicious that somehow the slave cylinder has "jammed" in the released position and that the car will have to be split. and that is a huge job. especially considering I just got it together. Failure of the clutch is also a remote possibility in my mind.

But this seems far fetched to me as there is a ton of spring force it would have to hold against for that to happen.

Anyone have any thoughts that might help?

Any help is greatly appreciated.

Steve

[Rick Kirchner]

borescope thru the timing hole in the bellhousing, or the slot at the bottom, if it has those.

[Steve Demeter]

Good idea.

Just have to get hold of a borescope

[wake74]

Good idea.

Just have to get hold of a borescope

That's what I used on a previous E36 track rat. Small hole in the bell housing. Wireless boroscopes are cheap on Amazon. I think I paid like $35 for mine. Syncs to your phone, which makes it nice so you can operate the clutch and watch the screen at the same time, make records, take pictures, etc.

[kea]

Do not "re-grind" pressure plates..

[bob darcey]

Over-center the pressure plate spring?

[DaveW]

Over-center the pressure plate spring?

Even if you go over center, you will usually only degrade the spring force by yielding it. There still should be some contact pressure. And Steve said he checked the pedal motion to not over-flex the spring.

[mark elder]

I am a bit confused. You said

Got it back into garage, and there was a big puddle of brake fluid on the diffuser, but it was all at the front, none anywhere near bell housing. Looked closer and found that line had gotten pinched and that was where the leak was from.

Are you not going to replace the line, rebleed and see what happens? If the braided line goes into the bellhousing, then the hose can be fixed by putting a joiner at the site of the leak (save you splitting the car). You can then replace the hose properly at a later date.

Have you opened the bleed nipple to release any residual pressure in the slave?

What is odd is you seem to have had 2 things happen at once. No connection between the engine and the gearbox (no drive) and a pedal to the floor (I guess due to the leak).

You want to be able to 'see' if the input shaft in the bellhousing is turning when you turn the wheels. If so, then its bellhousing off.

[Steve Demeter]

The line apparently got pinched when installing the engine. Ham fisted mechanics (AKA the driver). New hose to replace is on the way. Attachment point is on outside of bell housing.

The pedal had only been depressed once and that was to set the stop.

When the hose blew and the clutch stayed released, that was the second time it was depressed with the engine running.

Thanks whoever said it but I did open the bleed screw for that exact reason as sanity appeared to have taken a holiday.

I do vaguely recall losing a -4 plastic plug somewhere on top of the engine a couple of months ago while putting all the plumbing back together.

Maybe it fell down the timing hole and things went exactly wrong and it somehow jammed up the works.

I am still going to procure a borescope and check on things. But I hope it is just one of the most unfortunate coincidences ever.

Keith, I reground the pressure plate because it was warped beyond Tilton's specs and the same document from Tilton said it was OK to do as long as you stayed above 0.525" thick , which it was. You know something I don't, probably from all your experience and now I will know better the next time. Thanks

[Steve Demeter]

Purchased -4 line and ferrules form a well known supplier. Arrived late yesterday. Tried to assemble this AM. Ferrules will not go on the end of the hose to save my life. Measured OD of teflon tube and it was 0.290". Seems a bit big. Old line measures 0.250".
Ferrules measure 0.250" id. They go on the old line just fine. Called the supplier, talked with one gentleman for a while. He was working from home and agreed that something was amiss. He was going to transfer me to "Jake" ( I did not get the name clearly) at the shop to have him look at what was in their stock. Got cutoff. Called back and got Jake and explained the situation. He went to the warehouse cut a piece of line and called me back. He said that the ferrules went on just fine but you had to "angle" them a bit and make sure that the cut was nice and square. I asked about the 0.040" discrepancy in the diameters and he said " well how do you think the ferrules crimp on the line".

Called a couple of well known folks and got the same "wtf" no way that will work.

So I ordered hose from Jeg's and we will see tomorrow.

One of the folks I talked with mentioned something about hearing of some bad hose but did not know any details.

Am I the only one who has experienced this or am I just incapable of assembling the hose?

[sc94]

From Pegasus;

Stainless Steel Braided PTFE Hose
Hose Size	Hose I.D.	Hose O.D.	Equivalent Tubing OD	AN Fitting Thread Size	Operating Pressure	Min. Bend Radius	Part No.
-2	0.079"	0.20"	1/8"	5/16-24	3000 psi	0.6"	3260?2
-3	0.138"	0.25"	3/16"	3/8-24	3000 psi	1.5"	3260?3
-4	0.197"	0.30"	1/4"	7/16-20	3000 psi	2.0"	3260?4
-6	0.320"	0.43"	3/8"	9/16-18	2500 psi	4.0"	3260?6
-8	0.420"	0.54"	1/2"	3/4-16	2000 psi	5.3"	3260?8

It looks like you might be trying to put a -3 ferrule on a -4 line?

[BeerBudgetRacing]

Good idea.

Just have to get hold of a borescope

buy 2: ( don't know this particular one but I have 2 different ones and they both work well)
https://www.amazon.com/Inspection-Fa.../dp/B071HYRPND
https://www.amazon.com/Seesi-Endosco.../dp/B07PBF6DX5

One in the trailer, one in the garage. Cheap and useful.

[Steve Demeter]

I ordered the right pt# from the supplier (for a -4 ferrule). They confirmed the ID of the ferrule as being 0.250".

The OD shown on the chart is for the hose over the braid per the supplier.

Anyway, got it plumbed up , bled with solid pedal. Clutch does not disengage when pedal is depressed full travel.

Looking at what can be seen (not very much due to space constraints) there appears to be no movement of the slave. No loss of fluid is observed. Wondering where all that fluid that the master is moving is going.

Pedal is totally hard and feels "normal".

Aren't race cars fun!!!

[BeerBudgetRacing]

I ordered the right pt# from the supplier (for a -4 ferrule). They confirmed the ID of the ferrule as being 0.250".

The OD shown on the chart is for the hose over the braid per the supplier.

Anyway, got it plumbed up , bled with solid pedal. Clutch does not disengage when pedal is depressed full travel.

Looking at what can be seen (not very much due to space constraints) there appears to be no movement of the slave. No loss of fluid is observed. Wondering where all that fluid that the master is moving is going.

Pedal is totally hard and feels "normal".

Aren't race cars fun!!!

Remember it doesn't move that much.

Don't know the configuration of a Citiation's plumbing, but on my 94 VD I could leave the cap off the master and the bleed valve open and all the bubbled would exit overnight. Once push of the pedal finished it.

You say it's totally hard? Never seen that in a clutch

With the hose issue (and the "hard" pedal) make sure there is nothing in the line blocking/plugging the holes into the expanding part of the slave and just bypassing the fluid to the bleeder. I had that once (tiny piece of the internal hose) and it gave me fits.

I wouldn't be surprised if you'll need to split the car in the end.

[mark elder]

My guess is the slave was pushed out too far at the beginning of all this when you were checking the pedal throw. This it has got stuck and will not retract. Yes these do not move far but it does depend on the 'starting point'.

With the slave pushed all the way in, there should be a little clearance between the thrust bearing and the clutch cover fingers. Lets say 3mm, others can chip in with their magic number...

The clearance varies between clutch covers and plates (a little) and flywheels as they are all of various thicknesses.

I think you have to take the bellhousing off, and see what is happening. The push the slave all the way in. Measure the clearance. Ask if you are not sure how to do this.

It is possible that you have, say, 10mm clearance and the slave has just popped out. Or it just got pushed out by having a very long pedal travel.

Report back to the family.

[ejsprint30]

Scott Young set my air gap at .200 with the components he assembled based on measurements I gave him. I set my pedal stop the same way as above, and so far it has been spot on. For Ztec

ej

[Steve Demeter]

I plan on splitting the car after last night. Something is goofy in the bellhousing.

more fun and games

Thanks to all

[Steve Demeter]

Beer, By hard I meant that it was perfectly normal. I should have been more clear.Could push pedal all the way to the stop and clutch would not disengage. I am still trying to figure where the fluid went by pushing the hard pedal and no movement detectable at the slave. Ho fluid appeared anywhere as leaks and bleed screw was closed. Even watched it on a borescope, but the view was terrible due to the geometry.

[Rick Iverson]

Remember it doesn't move that much.

Don't know the configuration of a Citiation's plumbing, but on my 94 VD I could leave the cap off the master and the bleed valve open and all the bubbled would exit overnight. Once push of the pedal finished it.

You say it's totally hard? Never seen that in a clutch

With the hose issue (and the "hard" pedal) make sure there is nothing in the line blocking/plugging the holes into the expanding part of the slave and just bypassing the fluid to the bleeder. I had that once (tiny piece of the internal hose) and it gave me fits.

I wouldn't be surprised if you'll need to split the car in the end.

Paul;

Per chance, have you replaced the stock midyear clutch slave (read: crummy) with a 1.875” Tilton (shortest available, perhaps modified) and a modified bell housing/reservoir to accepts said?

If not, I think the is a reasonable engineering challenge. Thoughts?

[BeerBudgetRacing]

Paul;

Per chance, have you replaced the stock midyear clutch slave (read: crummy) with a 1.875” Tilton (shortest available, perhaps modified) and a modified bell housing/reservoir to accepts said?

If not, I think the is a reasonable engineering challenge. Thoughts?

In the 7 years I had the car I never had a clutch slave problem. Clutch action was better than the RF01.
It was not a Tilton unit. Split the car many times, replaced the disc and rebuilt the master but never touched the slave.

[SteveG]

For a Tilton OTII single plate clutch, does anyone know -

Assuming zero clearance between TO bearing and fingers,
What is the minimum slave travel distance to fully release the clutch?
What is the maximum travel distance?

FWIW, I've can't find the answer on Tilton's website and I have not called them.

Steve

[Steve Demeter]

And what a surprise. First thing: Throwout bearing is "squisheed".
Second thing it will not come off of "piston" and neither will piston come out of "cylinder" Was able to bet a gear puller under to bearing and pull it apart, but inner race was still on piston.
removed plastic cover on end of cylinder and was able to just get pulled on inner race and pull "piston out with inner race attached.
Never could get the 2 separated.

Galling on both ID and OD of piston. Galling on the part of the cylinder that ID of piston rides on. In other words shot.

But why?

I am going to try Scott Young tomorrow and see if he can supply me a new one. Any other suggestions?

Also going to have him rebuild clutch cover just on general principles.

[mark elder]

So no surprise the slave is jammed. The SAAB 900 slaves are plentiful and cheap (new is about $150+). Sadly, I carry a spare O ring set and a rebuilt slave to the track every time (OCD).

What is odd is you rebuilt the unit and noticed no wear. Now it is stuffed. Odd that there has been only a few pumps on the pedal. I wonder if the bearing was only half on and hydraulic force jammed it on (maybe at a angle?)

Post pictures.

[Steve Demeter]

Quite possible that I got the bearing on somehow incorrectly. Pict would not tell a whole lot at this juncture except to show extreme galling on od of "tube" inside slave cylinder, destroyed to bearing and piston with inner race stuck to it.

Somewhat relieved to hear that these things do get jammed from time to time. Now at least I know that I do not have all that of an unusual issue. Will sleep better!!

[tlracer]

I am not hugely familiar with the SAAB slave cylinder, so apologies in advance if the following are wide of the mark. A couple of thoughts:

- Could the scoring/stuck piston be the result of debris from the split line being pushed through?

- If the damage suggests the piston got skewed, could there be some issue with the clutch springs, so one side of the fingers is stiffer than the rest (broken spring, debris?)

[Steve Demeter]

No debris from broken line. Actually cracked is a more proper description. No broken spring debris noted.

But springs appear flat whether bolted up to flywheel or sitting loose. They are supposed to be cone shaped, high in the center.

I think that this may have allowed the piston to overtravel and get sideways a bit and stick.

Thanks for all suggestions. They are valuable.

The rest is history.

[Rick Iverson]

………but on my 94 VD I could leave the cap off the master and the bleed valve open and all the bubbled would exit overnight. Once push of the pedal finished it…...

Break fluid is hygoscopic, and by opening it up to the atmosphere, it absorbs moisture from ambient humidity. This results in the boiling point significantly lowering, and more prone to brake fade. Do you then bleed out the entire system?

[tlracer]

But springs appear flat whether bolted up to flywheel or sitting loose. They are supposed to be cone shaped, high in the center.

I think that this may have allowed the piston to overtravel and get sideways a bit and stick.

Not exactly the same, but this thread had mention of a similar issue where the fingers/springs on a Tilton clutch weren't as they should have been:

https://www.apexspeed.com/forums/sho...=tilton+clutch

That was due to one of the friction disks being too thick, could your problem be related in any way?

[Steve Demeter]

Maybe, but it is a single disc and the thickness is to spec. (.130" brand new). Thanks for the suggestion!!!

[Purple Frog]

Not that it applies... I bought one car years ago and immediately discovered the throwout bearing to be installed backwards. OUCH!

[tlracer]

Maybe, but it is a single disc and the thickness is to spec. (.130" brand new). Thanks for the suggestion!!!

Just throwing in ideas...if the disc was accidentally reversed, would that explain the fingers being flat and/or slave failure?

[BeerBudgetRacing]

Break fluid is hygoscopic, and by opening it up to the atmosphere, it absorbs moisture from ambient humidity. This results in the boiling point significantly lowering, and more prone to brake fade. Do you then bleed out the entire system?

Yes, good point. But remember, this was the clutch.
So not so much fading involved since I only use it in the pits and when I miss a shift/

[Steve Demeter]

I learned the hard way long ago not to install the disc incorrectly. And I keep that one on the shelf to remind me>

Again, Thanks for the ideas

[kea]

Maybe, but it is a single disc and the thickness is to spec. (.130" brand new). Thanks for the suggestion!!!

AP lists a new 7-1/4" sintered disc as 1.03" thick

[Rick Iverson]

Yes, good point. But remember, this was the clutch.
So not so much fading involved since I only use it in the pits and when I miss a shift/

You are most correct, what the heck was I thinking.

[Phil Creighton]

Had this happen on an S2 once - these SAAB units have very little tolerance not to jam at full extension. We couldnt get it apart afterwards.
phil

[Steve Demeter]

Phil,
Yep, Had to use a gear puller to get it apart.

Keith,
We are both wrong, the spec is new .103 a5 least for a tilton disc.I have been reading it wrong or remembering it wrong. I did measure it again just to be sure and 0.103" is what the brand new tilton disc checks and that agrees with the tilton supplied instructions.

Obviously we both got the decimal point in the wrong spot LOL 1" + thick really caught my eye!!

[Rick Iverson]

I think you have to take the bellhousing off, and see what is happening. The push the slave all the way in. Measure the clearance. Ask if you are not sure how to do this.

Mark;

I am asking, please?

[Rick Iverson]

Phil,
Yep, Had to use a gear puller to get it apart.

Keith,
We are both wrong, the spec is new .103 a5 least for a tilton disc.I have been reading it wrong or remembering it wrong. I did measure it again just to be sure and 0.103" is what the brand new tilton disc checks and that agrees with the tilton supplied instructions.

Obviously we both got the decimal point in the wrong spot LOL 1" + thick really caught my eye!!

This is of my new 5.5” disc from Pegasus. I see it at 0.106”.

[BeerBudgetRacing]

You are most correct, what the heck was I thinking.

Your point was a good one though. Something to remember when exposing the fluid to air.