Loose, Wiggly Reservoir on Clutch Master Cylinder

I just noticed that I can wiggle the reservoir on the clutch master cylinder. It's probably been that way for years. Is it supposed to wiggle? I don't have any signs of leakage but I do an inordinate amount of rough, off-road driving and I don't want it to suddenly come loose.

 

It's fine, there is a O ring that seals it and if it's not leaking, don't worry about it. The actual entire assy..........yeah, that would be an issue though an easy one to likely fix.

 

I have the same problem with a brand new Aisin clutch master cylinder purchased online from a local dealer and picked up locally; no shipping. Mine is a '96 4x4. I am in the process of replacing both master and slave due to clutch performance issues. I have already installed the master but have not hooked anything up or filled with fluid. I wasn't paying enough attention before I installed it, but it does wiggle easily. I am confused about fxntime's reply; what do you mean about "The actual entire assy..."? The plastic reservoir can be easily wiggled, but it is in no danger of coming off; it's just that it is not seated firmly to the metal of the master cylinder. I'm wondering if I should take it out and back to the dealer before I go further with this job.

 

Reservoir will wiggle as the seal under it is thick. Tighten it up and it WILL break (been there done that) as long as the cylinder is thought against the firewall your good.

 

Thanks very much for the reply, but to be clear, I don't think the seal is very thick (in fact, I thought it looked kind of thin and skimpy), and I would describe the reservoir as being pretty loose; it's not just the movement you could get from something that was firmly attached to a "padded" surface such as would be the case if the plastic reservoir base was snugged up to the metal of the cylinder with a thick and not-too-dense seal or washer. I'm not worried about it coming off; just don't know if the looseness would allow air entry into the cylinder from the joint of the reservoir and the cylinder. Or fluid leakage once it's full and pressure is applied to the whole system.

 

Probably not a big deal if the clutch pedal is firm and operates well. Cheap insurance would be a bead of rtv around the base of the reservoir / mc connection and secure it in that way. Like most things with that stuff, it’ll take extra effort to remove and repair things later.

 

The pressure is downstream of the piston. Nothing above the piston has pressure acting on it.

If air was leaking in somewhere you'd have fluid leaking out in that same area. If you don't see any leaks you are fine

Yes the reservoirs all wobble but it won't come out of there. Have you ever tried to remove one of them? It actually takes quite a bit of prying to pop it past the seals. Like so much prying you'll be worrying about cracking the plastic. Oftentimes they'll stretch and twist but stubbornly won't come out

 

I haven't gotten that far to know if pedal is firm and operates well; am installing new master and slave and have not filled with fluid and bled. I didn't want to take that step until I was sure it wasn't a defective part. The old master I took off did not have that issue; reservoir and cylinder were quite solid to each other.

 

@b_r_o You were answering as I was answering @Dalandser. I see you are telling me it is common for the reservoirs to wobble (or jiggle or wiggle); they are not tightly secured to the cylinder (even though the one I just took off was tight to the cylinder; no wiggling), and that joint, or interface, is not generally a source of leaks. As I said to @Dalandser, I haven't put fluid in yet, so I don't know if there are any leaks. Are the seals people are referring to inside the cylinder? All I see from outside is a thin washer or spacer.

 

The rest of the seal is down in the cylinder

Just Google a picture of reservoir seals

 

Ok, that makes sense, and makes it understandable that the reservoir could be loose but still have a good seal from the cylinder.

 

Thanks to all for the replies.

 

A further note for anyone interested: I took the master cylinder back to the dealer to show the parts guy. He didn't know for sure if it was ok and they didn't have another in stock to compare, but they had one in KC warehouse. He suggested I buy online like I did for the first and have it shipped to them, and we could see if there was any difference. Then I could keep whichever one I wanted and they would refund the other. So I did that, and it turned out the second one was the same as the first (from a different batch, by the way, according to the label on the packaging). I kept the first one, installed it along with new slave cylinder, filled and bled, and...magic. My clutch is working properly and I see no leaks from the master cylinder. So it seems those saying the looseness doesn't matter are correct. I'll come back with a PSA if I have any trouble with that master down the road. Thanks again to all who replied.