Slave Cylinder Push Rod Lost in Bell Housing

[Cloudbase]

I was replacing Fletch's clutch line with a UUC line tonight and managed to blow his slave cylinder contents into the transmission bell housing. Up until that moment the job was going super smooth. I got the old line off in five minutes. The technique I used on my old line worked perfect. We bled it using my homemade tool. I felt the push rod against the release lever before I tightened the slave down. When I stepped on the pedal it blew the push rod into the bell housing. All I can think of is that the push rod was aligned on the side of the release lever cup, because I felt it resisting the release lever when I lined it up. I spent a few hours trying to fish it out and talking to Randy on the phone about dropping the transmission. We decided to sleep on it before making a decision on how to get it out.

I've replayed the evening 100 times in my mind and not sure how it happened. I was aware of the danger of this happening, but I took my time aligning the slave cylinder before I tightened it down. When I pressed the push rod against it it resisted enough to push the slave cylinder off the transmission bolts. I was positive it was on. The only other possibility I can think of is that I had the pressure bleeder still connected. The pressure was probably about 13 psi as I don't like to over pressurize the system when bleeding. I've done this job on my car with no problems and much more complicated jobs before. I try to work methodically and be thorough in my execution Has anyone had this happen? How did you get the push rod out? ARGH!

Re-thinking it I'm sure it wasn't the bleeder. I remember depressurizing the bleeder before I got in the car, I just didn't unscrew it from the reservoir because we were going to flush the brakes next. If it was pressurized the fluid would have continued to drain at a fast rate out of the slave cylinder body when it popped out.

[Jeremy]

Bummer, Alex. Really sorry to hear that happened. I have no advice to give, but I hope you guys can figure out a simple way to resolve the issue.

[Vinci]

*cringe*

How much fluid did you lose? If it got on the clutch disk... it might have ruined it.

The only option for retrieving it, that I can think of, would be some carefully-bent wire and a magnet. Well, aside from referencing that ominous link in my signature...

[deilenberger]

BTDT on my E36 M3. Not quite the same since I didn't have the pressure bleeder attached at the time (which I think was your problem.)

After a few hours of trying to get it out with various magnets (on sticks, on strings, on wires, you name it..) We R&R'd the transmission and it fell out when we pulled the bell housing back. IMHO, once it gets under the flywheel there is no way you're getting it out other then pulling the tranny.

[Cloudbase]

That is one good DIY Vinci! It makes the prospect of pulling the transmission much less daunting. It didn't shoot that much fluid out, I'd say about half a shot glass. I did think about that at first clutch contamination, but if it was the bleeder that caused it then the release lever would have blocked it. We will know if we pull the tranny, the other option is to ship it to Randy (it was heading there anyway), Fletch is researching that now.

I don't think it was the bleeder Deilienberger. I think I depressurized it before I got in the car - see my first post...

[Vinci]

It wasn't the bleeder. The pressure wouldn't have been any higher than ~25psi (the reservoir won't take more than that), and the system works on FAR higher pressure than that.

[deilenberger]

I was aware of the danger of this happening, but I took my time aligning the slave cylinder before I tightened it down. When I pressed the push rod against it it resisted enough to push the slave cylinder off the transmission bolts. I was positive it was on. The only other possibility I can think of is that I had the pressure bleeder still connected. The pressure was probably about 13 psi as I don't like to over pressurize the system when bleeding

What I was reading was the bleeder was still connected and the system under pressure when you tried installing it.

Did I read that correctly?

If so that means the slave pushrod is all the way out - which will add greatly to the risk of it falling off. Rob Levinson warned me (before I dropped mine, I should have listened) that the rod is retained by a plastic guide in the slave cylinder. With age - the plastic wears and the rod can then easily fall out.

If the piston was fully extended, I imagine the possibility of that happening is much greater. As far as the piston coming out the end, I dunno if there is a retaining clip for the piston, or if it uses the plastic guide at the end of the cylinder (I guess I could look at the one I removed last week, it's sitting in my garage..) If it's the plastic guide - same scenerio. It gets old, it shrinks, it is weak, doesn't take a lot for it to pop out.

That was my thinking, having BTDT.

It wasn't the bleeder. The pressure wouldn't have been any higher than ~25psi (the reservoir won't take more than that), and the system works on FAR higher pressure than that.

That's correct - it works on far higher pressure with the system FULLY assembled (and the clutch fork pushing back on the pushrod from the slave cylinder..)

If it isn't installed and there is pressure in the system - I suspect the slave cylinder isn't meant to actually operate under those conditions. The official bleed procedure for the cylinder NOT in the bell-housing has a special tool that keeps the push-rod and cylinder fully compressed. There is a reason for that tool.

[Vinci]

That's correct - it works on far higher pressure with the system FULLY assembled (and the clutch fork pushing back on the pushrod from the slave cylinder..)

If it isn't installed and there is pressure in the system - I suspect the slave cylinder isn't meant to actually operate under those conditions. The official bleed procedure for the cylinder NOT in the bell-housing has a special tool that keeps the push-rod and cylinder fully compressed. There is a reason for that tool.

I guess I'm not sure where you're going with that. The slave cylinder was installed (albeit incorrectly) on the bell housing when the OP pressed the pedal down. That is the system being fully assembled.

Once the plunger in the master cylinder starts to be pushed in by the pedal, the fluid port from the reservoir is 100% cut off from the system. If it weren't, then the pressure generated by the pedal/master cylinder would blow the fluid back up into the reservoir and rupture it. With that in mind, the pressure on the reservoir from a bleeder is completely irrelevant to the operation of the system.

[steve f]

Bummer, unfortunately this stuff happens, usually at an inconvenient time.

I’ve never dropped a tranny from the Z3, but I have on a lot of other cars, so this might or might not work. Let me know.

I doubt that you need to pull the tranny all the way out to retrieve the lost parts. How about removing the bell housing to engine bolts and replacing one on each side with bolts that are about 1-1/2 to 2” longer that the stock bolts to use as guide studs. Install the guide bolts only about ¾” by hand. Don’t tighten them at all.

You’ll still have to drop the drive shaft and most likely disconnect the shift arm linkage, but then you only need to slide the box back far enough to pull the wayward parts out. Try to keep the box level and it should slide back easily without disturbing anything else.

I hope this is a simple solution. Otherwise, sorry I’ve got nothin’.

[Vinci]

Bummer, unfortunately this stuff happens, usually at an inconvenient time.

I’ve never dropped a tranny from the Z3, but I have on a lot of other cars, so this might or might not work. Let me know.

I doubt that you need to pull the tranny all the way out to retrieve the lost parts. How about removing the bell housing to engine bolts and replacing one on each side with bolts that are about 1-1/2 to 2” longer that the stock bolts to use as guide studs. Install the guide bolts only about ¾” by hand. Don’t tighten them at all.

You’ll still have to drop the drive shaft and most likely disconnect the shift arm linkage, but then you only need to slide the box back far enough to pull the wayward parts out and the tranny should slide back easily without disturbing anything else.
I hope this is a simple solution. Otherwise, sorry I’ve got nothin’.

The thing is that you really can't get to most of the bolts to swap them out like that, unless you take apart several other things. At that point, you're 90% of the way to having the transmission out entirely and being able to inspect the clutch.

Dropping our transmissions really isn't a bad job. There are a few one-time-use items that have to be replaced no matter what, but the work isn't difficult.

[osborni]

Likely the tranny doesn't need to come all the way off, just enough to get your hand in there to find the part. It's been a while since I did my clutch and can't remember all the details on how much space in in there.

[Joemamaman]

SteveF's idea is pretty good... if you feel you don't need to inspect the clutch (assuming brake fluid dint hose it down). Just remove all the tranny bolts while inserting a couple longer bolts for the trans to slide on back right? Keeps alignment... This would also help when re-installing a tranny too.

Worst case scenerio, if you're gonna pull a tranny (w/o a lift), then invest in a $80 Harbor freight trans jack (the one that is rated at 800 lbs). It makes removal and install incredibly simple, and effortless. Also works great for dropping rear subframes and differentials.

[jbrannon7]

You have one other choice, besides using a holesaw, which I have seen pictures of. On the front of the bell housing on the passanger side is a sheetmetal cover held tight by one 10mm bolt. That is part of the sheet metal spacer that goes all the way around the bell housing to engine mating surface. You might be able to bend that sheet metal back enough to get to the rod.

Joe

SteveF's idea is pretty good... if you feel you don't need to inspect the clutch (assuming brake fluid dint hose it down). Just remove all the tranny bolts while inserting a couple longer bolts for the trans to slide on back right? Keeps alignment... This would also help when re-installing a tranny too.

Worst case scenerio, if you're gonna pull a tranny (w/o a lift), then invest in a $80 Harbor freight trans jack (the one that is rated at 800 lbs). It makes removal and install incredibly simple, and effortless. Also works great for dropping rear subframes and differentials.

[afb]

The thing is that you really can't get to most of the bolts to swap them out like that, unless you take apart several other things. At that point, you're 90% of the way to having the transmission out entirely and being able to inspect the clutch.

Dropping our transmissions really isn't a bad job. There are a few one-time-use items that have to be replaced no matter what, but the work isn't difficult.

yep, pretty much. it's fairly simple & straightforward, but time consuming, and the top tranny bolts can be a bit of a pain.

[Randy Forbes]

You have one other choice, besides using a holesaw, which I have seen pictures of. On the front of the bell housing on the passanger side is a sheetmetal cover held tight by one 10mm bolt. That is part of the sheet metal spacer that goes all the way around the bell housing to engine mating surface. You might be able to bend that sheet metal back enough to get to the rod.

Joe

I had thought of that last night (while on the phone...) but I'm pretty sure that the oil pan will limit that to not doable.

After looking at the pictures, the only thing he'd accomplish is destroying the sheetmetal spacer__nothing to be gained here by trying__note the diagonal "line" representing the rearmost oil pan rail.

[djb2]

Getting brake fluid on the clutch disk isn't a complete disaster. Brake fluid really loves to mix with water and will readily rinse off. If the fluid is sufficiently diluted with water, the residue will evaporate with the water in the mixture.

[Joemamaman]

For the top bolts, I used lots of 3/8's drive extensions (some of them with wobble tips)... and that got them out easier than expected. (I believe 4cyl and 6cly have same bolt patterns, right?)

Also, if you need an E11 torx socket, let me know. I bought one (Snap-On) only to find 1.9's dont need them.

[deilenberger]

I guess I'm not sure where you're going with that. The slave cylinder was installed (albeit incorrectly) on the bell housing when the OP pressed the pedal down. That is the system being fully assembled.

What it appears he described was:

1. He may have installed the slave with pressure in it from the bleeder.

2. If he did - the pushrod was extended, and this is likely what caused the difficulty in installing it.

3. It sounds as if "When I stepped on the pedal it blew the push rod into the bell housing.") the pushrod was never in the receiver "cup" on the clutch fork.. due to it being extended and "When I pressed the push rod against it it resisted enough to push the slave cylinder off the transmission bolts"..

And when he stepped on the clutch pedal the lack of a pushrod caused the piston to pop out.

Once the plunger in the master cylinder starts to be pushed in by the pedal, the fluid port from the reservoir is 100% cut off from the system. If it weren't, then the pressure generated by the pedal/master cylinder would blow the fluid back up into the reservoir and rupture it. With that in mind, the pressure on the reservoir from a bleeder is completely irrelevant to the operation of the system.

It is IF IT'S ASSEMBLED CORRECTLY. This rather obviously was not. If it had been we wouldn't be having this discussion.

If the bleeder causes the slave cylinder to be fully extended (which it sounds like) - and that caused the misalignment of the pushrod - then the bleeder being connected and pressurized IS the cause of the problem.

Think through the sequence of events that could lead to the situation he is now in.. and if you can come up with an alternative, I'm all ears. The systems aren't magic, they are well known, and the bleeding and assembly is pretty well documented in lots of sources.

[jbrannon7]

Assuming all the parts that went into the bell housing are magnetic, you can get a very strong magnet and draw the parts up to the opening from outside the bell housing. Put the magnet at the center of the bottom of the bell housing and work it up to the slave cylinder opening. Might work.

Joe

[Cloudbase]

When I first wrote the post I was thinking the bleeder was under pressure, but thinking about the sequence of events it wasn't. Sorry to spark an unnessesary debate. I pretty sure the plan is to do it right and drop the tranny. After a nights rest and reading the DIY it doesn't look that bad. While it's out we can do the shift pins and mounts. I'd like to have the satisfaction of solving the problem too. I'll keep you updated...

[stanley]

Assuming all the parts that went into the bell housing are magnetic, you can get a very strong magnet and draw the parts up to the opening from outside the bell housing. Put the magnet at the center of the bottom of the bell housing and work it up to the slave cylinder opening. Might work.

Joe

Yes I agree, poss a magnet on a piece of mechnics wire and fsh it out!!!

[IslandS62]

CB, try PMing member Thrlls or ZZZing. Both are (or were) members here. When they tried the clutch line on ZZZings car this happened to them also, and it is a major reason why, 3 years on, I still have a new un-installed UUC clutch line. IIRC ZZZing had the car towed to a shop to drop the tranny, but maybe he can advise you on what needs to be done.

[deilenberger]

Yes I agree, poss a magnet on a piece of mechnics wire and fsh it out!!!

Dunno if you ever tried this.. but there is actually very little clearance in the slave cylinder hole, and where it's located (up high in the transmission tunnel) makes it very difficult to manipulate anything through it.

BTDT. Tried for several hours. No success. The magnet has a real affinity for the clutch, flywheel and pressure plate (which are made from steel). Probably a 1 in 100 chance of getting the pushrod out, and likely 0 chance of the piston.

[Cloudbase]

I think the best solution is to pull the Tranny. That way we can inspect the clutch and clean it if necessary and make sure we got everything from the Slave Cylinder. Before I installed the slave cylinder I pushed the push rod in to make sure it felt bled. I don't feel like it was extended far, but there is a reason I missed the release lever cup so perhaps that was the cause. I've been thinking obsessively about it all day and I'm actually looking forward to pulling the gearbox. I was going to pull mine at some point to do my shift pins, but was waiting for my clutch to warrant it.

[jbrannon7]

Dunno if you ever tried this.. but there is actually very little clearance in the slave cylinder hole, and where it's located (up high in the transmission tunnel) makes it very difficult to manipulate anything through it.

BTDT. Tried for several hours. No success. The magnet has a real affinity for the clutch, flywheel and pressure plate (which are made from steel). Probably a 1 in 100 chance of getting the pushrod out, and likely 0 chance of the piston.

You guys are thinking inside the bellhousing, I am suggesting outside the bellhousing. A strong magnetic field will penetrate the aluminum.

Joe