Maverick13

I tried posting this to the general tech board a few weeks ago and couldn't get any help over there so figured I'd try my luck here. Hopefully someone can point me in the right direction...

Anyway, when I start off to work in the AM the clutch pedal is fine, no noises, no stiffness, nothing unusual. However, mid-commute I notice the pedal getting stiffer (hydraulic clutch). And toward the end of my commute the pedal is really stiff and makes a "popping" sound when the pedal hits the floor. After the car sits for awhile, and I go to drive again, it's the same thing. Starts off fine, gradually gets stiffer, then the popping noise.

What could this be? I'm guessing it has to do with the hydraulics (master/slave), but I don't get why pressure is building up in there, nor do I know what that "pop" is.

I've also noticed that when the pedal feels tight that I don't have to put the clutch all the way to the floor in order to shift.

Anyone have any ideas?

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Maverick
1989 Formula 305 TPI 5-speed
Suspension mods, stock engine

ev305tpi

iTrader: (3)

Not that this is any help but my '87 GMC full size pickup did the same thing and I always wondered what it was. It had a 305/4 speed with a hydrolic clutch and it would do the same exact thing, it always seemed at least to me that it did it worse on days it was raining out - I put a new slave cyl, slave master and a new slave line in it and it still did the pop and thats the way i left it when i sold it.

Erik
86 IROC Z
Silver Glasruit paint on red deluxe int
GM crate 305 TPI

Blade

It's called a "hydraulic clutch"...

327 firebird

Mavrick, I had the same problem. It started after I put in a brand new tranny and throw out bearing. Now I don't know to much about this but it did stop after a while. My guess is that the new throw out bearing need to break in after a little bit and was sticking a little bit on the sleave that it rides on on the tranny input shaft causing the extra pressure and the popping sound was it finally moving. Now this is just my guess because after a while it broke in and went away. Did you happen to recently change the trow out bearing or tranny or the sleave around the input shaft. Also if not you might want to check it or put a little grease in that spot. I hope this helps.. Erik

Maverick13

Yeah, the problem started after I replaced the TO bearing and fork. It's been nearly 2 months now, though. I'm going to try to bleed the slave and see if that helps at all. I'm convinced there's air in the line because when the guys put in the new fork and bearing they were kinda quick when they put the tranny back in. they easily could have gotten some air in there if they didn't hold the slave together the right way.

This raises another question, does this sound like air in the line? After the car sits for awhile it's fine. It's only after repeated pumping of the clutch pedal that it starts to stiffen up. Thanks.


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Maverick
1989 Formula 305 TPI 5-speed
Suspension mods, stock engine

merf23

It doesnt sound like a hydraulic problem...sounds like the T/O bearing (most likely hanging up as mentioned) or pressure plate.

327 firebird

Well I'm 99.9% positive its not air in the lines. You would actually have the oppisite effect. Your pedel would be spongy and really easy to push down to the floor. You would also have problems disengaging the clutch and may grind gears depending on the severity if you had air in the lines. I'd check what I mentioned before. If you find no problems there make sure they installed the right parts. I know the V-6 and V-8 clutch forks are different (having swapped a V-6 to a V-8 in my firebird) Also the Firebird V-8 forks are different from the rest of the standard chevy and pontiac V-8 forks. And if all else fails you could try to completly drain, flush and refill your hyd clutch with new clean fluid. Might want to do that anyways since its probally been in there a while. Anyways when changing your fork and TO bearing all the do is unbolt the slave cyclinder from the bell houseing. It is comletely sealed. You can even take the rod and boot out that pushes the clutch fork and its still sealed. So I really doubt there is air in it. I'm still betting the TO bearing is catching on that sleave. Check it out. Also it might just break in and you will have no problems in a little while. Mine took a couple of months to break in, and its fine now.

327 firebird

Oh yeah I forgot to mention... the hyd clutch is self bleading it takes a lot of pumping to get it to be good and stiff but in two months of driving it you should have all the air out by now. I don't know why the put a bleed port on the slave cyclinder maybe its faster to bleed if its completely dry.

Maverick13

Interesting. Okay, so if air in the line doesn't cause stiffness, what would? It's hard to describe exactly what's going on with the clutch, but basically it feels like the pedal gets stiffer as I drive. For instance, if I drive to and from the grocery store (or where ever) the pedal feels fine, no stiffness. But if I get stuck in stop and go traffic (thereby having to pump the clutch a lot during stop/starts) the pedal gets stiff and the popping begins. On my foot, it feels as if there is more tension in the pedal (thereby implying something w/ the hydraulics). Hell, my left foot is even sore lately just from driving.

I really don't think it's the TO bearing, though. This problem didn't start immediately after the new bearing and fork were inserted. It started roughly a few weeks after. Had it begun immediately, I would have taken the car back to the shop.

Any ideas? Thanks.

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Maverick
1989 Formula 305 TPI 5-speed
Suspension mods, stock engine

327 firebird

Ok the only thing I know that will cause stiffness is the TO bearing getting caught on something. It is also possible they put it in backwards. When its in backwards it will ride nice for a while and then a few weeks later go out. Also the pivot point on the fork may not be lubed either. The only thing that can cause stiffness in a HYD system is resistance causing more pressure to push it. I know I had to study Hydraulics because I'm an aircraft mechanic. Check to make sure your rubber clutch dust boot is still good... no rips or anything. If it is or its missing forigen object such as pepple may get caught up in the pressure plate or TO bearing causing this. Also with mine it didn't start right away and didn't happen all the time. You might want to see if you can access the area by pulling off your clutch boot and look in there and maybe see if you can get any grease in there with out pulling everything apart. Also go back to that shop and talk to them about it.

Beast5spdGTA

I know this is an old topic, but my 91 firebird TBI 5 speed is doing something similar. The car has been sitting for 8 months, no the pedal effort is very hard and sometimes won't disengage the clutch at all. It was fine before I left for college, now i can hardle drive it. Also it has always made a clicking noise about half way through the pedal travel. Thanks