What's wrong with my car's clutch?

December 2, 2007 9:23 PM

Standard-transmission-filter: the point of engagement of the clutch (in my mid-90s Acura Integra, if it matters) has suddenly moved, and I now have to push the clutch pedal almost to the floor in order to get the transmission to disengage. What's going on, and how much is it likely to cost to repair?

Coupled with a shift in the pedal's point of engagement has been a drastic loss of "springiness" in the clutch pedal until it reaches the point at which the transmission engages.

Any ideas what might be causing this?

posted by killdevil to Travel & Transportation (18 answers total)

Have you checked your transmission fluid lately?
posted by DMan at 9:30 PM on December 2, 2007

Also check out this guide for trouble shooting a hydraulic Integra clutch system.
posted by jaimev at 9:35 PM on December 2, 2007

Theoretically, it should have been checked by Jiffy Lube the last time I took it to them, around 1000 miles ago. Checking/topping-off transmission fluid is supposed to be part of their basic oil-change service.
posted by killdevil at 9:39 PM on December 2, 2007

As DMan points out, it's almost certainly low fluid. On your car, it should be next to the brake fluid reservoir under the hood directly in front of the driver's seat. It's clearish with a black cap. The clutch fluid reservoir is the smaller one.

If it's low, fill it back up with DOT3 brake fluid and check it often. If it continues to leak, look for a leak where the clutch piston goes through the firewall in front of the pedal.

If the fluid isn't low, either your master or slave cylinder is going out. I have a '91 Accord with around 250k and all original clutch parts, so I doubt that's it, though. I once had nearly all of my fluid disappear, but after driving to the parts store with no clutch (not good on the starter, but it can be done in a pinch!), but after refilling it I had no further leakage, oddly.

As far as the cost to replace, you can get the part for as cheap as it comes (presuming you want an OEM part and not some aftermarket or rebuild) from Majestic Honda at hondaautomotiveparts.com. I swear by them.

I don't know what the book time for the replacement is, but the master cylinder is a 20 minute job for an experienced Honda/Acura tech. I have a fellow that works at the dealership do all my work for cash. My brake master cylinder cost me $20 plus the cost of the part, which wasn't too cheap, since I had to buy it from the dealer, being an OEM parts snob and needing it quick. ;)

If it's run too dry, you might have to bleed the line to get the air out before it'll work right. If you have an 8mm wrench, it's dead simple to do if you have a friend and can find the bleed screw, which on my Accord is on the passenger side about halfway down on the front side of the engine.

Since you say it still functions, you probably won't have to bleed, if you get some fluid in it pronto.
posted by wierdo at 9:41 PM on December 2, 2007

OK, just to clarify -- there are two different types of fluid we're talking about here. There's transmission fluid, which is used in automatic transmissions... that's what they check at Jiffy Lube (and really, they don't. They just pretend they do. Those "1 billion point inspections are a giant scam.) Then there's clutch fluid, which is hydraulic fluid that transfers the motion of the pedal (aka 'Master Cylinder') to the actual clutch mechanism (aka 'Slave Cylinder').

What you're low on is 99% likely to be clutch fluid since it still works. Just go get some more; the kind you need will be printed directly on the cap of the proper container under your hood. If it's not the fluid, then you will either need a new master or slave cylinder. The master cylinder is easy. The slave cylinder is an engine pull.
posted by SpecialK at 10:27 PM on December 2, 2007

Also, please don't take your car to Jiffy Lube for anything. They're notoriously awful. Find a mechanic you trust and take it there for everything from oil changes to brake work. Midas, Meineke, Jiffy Lube, etc are all horrible.
posted by autojack at 10:35 PM on December 2, 2007

wierdo's right on. I've got a 95 integra and I had exactly this problem a couple years ago. Topping off the fluid in the small reservoir behind the brake fluid reservoir solved it. I also found that I could lightly pump the clutch pedal between shifts to get it back up off the floor as a stopgap until I could pick up some brake fluid for the clutch.
posted by Jeff Howard at 10:44 PM on December 2, 2007

N'thing clutch fluid. Fill it up and pump it a few times and it shoudl sort itself out.

From the symptoms suggested, if the fluid isn't low, then the most likely fault to my mind is bad master cylinder seals (the one at the pedal end). Let us know if topping it up worked at all.

Again, I'd also be looking for a leak somewhere to prevent recurrence.
posted by Brockles at 5:16 AM on December 3, 2007

And don't trust Jiffy Lube for anything more complicated than pouring oil. Find a real mechanic.
posted by Skorgu at 5:38 AM on December 3, 2007

Resolution (maybe): I topped the relevant reservoir off with what, to me, seems like an incredibly small amount of DOT3 brake fluid -- and the problem seems to have at least partially resolved itself.

For future reference, the transmission fluid reservoir should be filled until the small disk-shaped plastic "float" visible inside it is actually floating, right?
posted by killdevil at 6:39 AM on December 3, 2007

For future reference, the transmission fluid reservoir should be filled until the small disk-shaped plastic "float" visible inside it is actually floating, right?

RTFM. :)

Seriously. One of the things the owner's manual covers is the various and sundry fluids you need to watch, how to watch them, and how to fill them when needed.

I suspect the float needs to reach a certain level, but I don't know for sure. Ask the fine manual, it'll tell you.

Don't have the manual? Get one, and curse whoever lost yours. A dealer will be happy to sell you one, you can get them online. You want the owner's manual, not the considerably more expensive repair manuals. Unless, of course, you want to do repair work, in which case, maybe you do, but the factory repair manuals are aimed at professionals, there are third party repair manuals that are better suited for the shadetree mechanic.
posted by eriko at 6:50 AM on December 3, 2007

if the fluid got low enough to allow air into the system, you need to have it bled (it's basically identical to the brake system).

it's easy to do it yourself, but it only takes a mechanic a few minutes.
posted by klanawa at 8:48 AM on December 3, 2007

seems like an incredibly small amount of DOT3 brake fluid

Same for my Acura. It only takes a tiny amount to get things back in order. Dispose of the rest and keep an unopened can in the trunk just in case.
posted by Jeff Howard at 9:00 AM on December 3, 2007

Dispose of the rest and keep an unopened can in the trunk just in case.

Whilst that is certainly sound practice if you want to use the fluid in the brakes, it isn't necessary when being used for clutch fluid. Brake/clutch fluid takes in small amounts of water over time when exposed to air. When this fluid gets hot, the water boils out as air pockets and the brakes get spongy. Clutch systems don't generate enough heat for this to be an issue, nor are so critical in their application.

Never use brake fluid that has been open for more than a month in your brakes. Never use dot 3 in your brakes (it's shit!).
posted by Brockles at 9:55 AM on December 3, 2007

killdevil, there's a couple of markings on the side of the reservoir labeled Min and Max that tell you how much fluid they need. The proper amount is more than just the bare minimum to make the float float, but the clutch system does take what seems like a small amount of fluid.

To find the bleed screw, have a friend push the clutch in repeatedly while you look for the slave cylinder. You'll see it moving in and out as the clutch gets pushed in and let out. The bleed screw is very obvious once you find the slave cylinder.

Brockles wrote:
Never use brake fluid that has been open for more than a month in your brakes. Never use dot 3 in your brakes (it's shit!).

I'll tell that to Honda. ;) They keep changing the antifreeze (last time I had a hose replaced it was some blue crap), but the brake fluid is the same old stuff they've been using.

Just for future reference, bleeding the clutch is vastly simpler than bleeding the brakes, simply because there's only one slave cylinder, which means there's no special procedure, just "open screw, have friend press and hold clutch, close screw, have friend release clutch, repeat until no air remains." It will take you less time than it would take you to go to a mechanic and have them work on it, unless said mechanic is next door. ;)
posted by wierdo at 1:49 PM on December 3, 2007

I'll tell that to Honda. ;) The brakes are usually a closed system once installed. I would, personally, change brake fluid once a year if I was being super-efficient.

Although in practice, the shortest period between changes (only of my road cars, for reference) has been two years.

Antifreeze has anti-corrosives in it that can need changing (technically) every twelve months or internal engine damage can occur over time (furring up of aluminium head/block internal passageways. Brakes just get spongy. So they are avoiding the most expensive worst case scenario.
posted by Brockles at 2:13 PM on December 3, 2007

Thanks, folks! The problem is completely resolved... unless I have a leak somewhere in the system. That would annoy me.

I pronounce myself a satisfied user of Ask Metafilter.
posted by killdevil at 4:18 PM on December 3, 2007

Brockles, when I said changing the antifreeze, I was referring to HMC changing the formulation of antifreeze they have their dealers stock, not that they change my antifreeze every year. :p

killdevil, good to hear your resolution was simple.
posted by wierdo at 9:03 PM on December 3, 2007