Hi,

This is my first post, but I’ve been lurking around here for awhile. I have a completely stock 1988 CRX Si.

The problem: massive clutch slip, only apparent after about 20-30 minutes of driving.

The story (part I): At 163,000 miles the factory clutch started to slip. No big deal-I took the transmission off. I replaced: throw-out bearing, rear engine main seal, both transmission driveshaft seals, clutch disc (OEM Honda), and pressure plate (Exedy). The flywheel looked okay, so I left it alone. I reassembled the car and 40 miles down the road, the clutch started slipping. It got worse too, and I could barely drive it. It seemed to like to slip only after it had gotten warmed up; when the engine/trans was cold, the clutch would grab normally. I do not drive aggressively and can count on one hand the number of times I’ve been over 4k RPMs.

The story (part II): after reading on this site and others about how dumb it was not to replace the flywheel, I decided to take the transmission off again. I had put 246 miles on the clutch, with most of those being highway/Interstate.
This time I replaced: clutch disc AND pressure plate (Exedy), flywheel (remanufactured unit from Standard Flywheel). I cleaned both mating surfaces very well and did the best, most careful job I knew how to do when reassembling everything. I drove about 40 miles down the road back to my apartment, and it started slipping just like the previous clutch!!! I couldn't believe it, and am running out of ideas of what might be wrong.

I made the following observations about the very low-mile, slippy clutch (from Part I):
There were intermittent spots that resembled the “hot spots” I had seen in pictures on the Internet on the flywheel. The clutch itself actually looked pretty good. But there were smooth areas on both sides of it. I am wondering if these are normal? The old clutch (factory 1988) was very smooth on both sides. (I am more familiar with wet, multi-plate clutches on motorcycles.)

Do the clutches for these cars (OEM Honda and Exedy), for some reason, require a break-in that includes really bad slipping when the car gets warmed up??

Here are some pics of the OEM flywheel and low-mile clutch that slipped terribly:

 

Oh yeah, I also replaced the clutch cable and adjusted it PERFECTLY-to the Honda Service Manual spec!

 

The flyhweel looks burnt as you said from excessive slipping. Have you checked to make sure that the spring on the release fork has good snap back? If it doesn't it may make the clutch slip without you slipping the clutch physically.

I always break my clutches in, I make sure to do it in the city as apposed to the highway because you are supposed to show it different RPM but if you do it on the highway I'v heard that the clutch gets really hot and could cause a glaze over effect making your clutch slip.

 

Yeah, I replaced that spring for the release fork. Funny that the guy at the Honda dealer parts counter said not to worry about it. Said something about he's only ever ordered 2 or 3 of them, and that's because they were broken. I didn't listen to him cause I know that springs wear out. With 163,000 miles, I went ahead and replaced it. It did make a noticeable difference in the pull of the lever.

With the second new clutch (the one it still has in it now) I drove it around about 10 miles on country backroads before going on the highway. But that was pretty much just locking it into 5th gear and cruising at 3000 RPM for 40 minutes. I guess I wouldn't think that the clutch would get overheated just cruising.

How long do you drive it around the city? Like->do you drive for 20 minutes or so and let it cool down. Or more like a couple hours?

 

Update: I talked to a "Technical Coordinator" from Exedy. I showed him the pictures and shared my story.

He says, "It definitely does not sound like the clutch. You either have a broken differential in the transmission or a broken CV joint on one of the axles. The wear spots seem normal for a flywheel that was not resurfaced."

I am having trouble finding information about the differential. I know the symptoms of a bad CV joint-terrible clicking. This car will click if i make a fairly sharp turn, but otherwise the driveshafts seem fine. A local transmission shop said they are kind of a pass/fail kind of part; they either work, or they don't.

What are the symptoms of a failing differential in these cars?

 

having a simlar problem take a took at my thread and see if we have the same problem maybe we can both get some answers
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/crx-y1-trans-trouble-can-you-diagnose-2748387/

 

I'm a machinist by trade and have building motors for about 8 years. The problem looks like you didn't resurface the flywheel. Whenever you replace the clutch its best to take the flywheel to a machine shop and have it ground. You usually only take about .003 to .006 of metal off the surface to insure that the new clutch has a prefectly smooth surface to engauge to and all the the new surface and clutch will wear together. Get the flywheel resurface. Cost about 25 to 45 depends on the shop. It will stop the slipping

 

Yes, I explained above that I replaced the flywheel. That did not solve the problem.

 

When I had my stock clutch replaced (88 si) I ran it easy for 500mi and then it slipped. I took it back to the clutch shop and his response to me was " the flywheel had to be stepped. It has to be cut to correct it"

From what I got out of it was the friction surface had to the stepped up farther from the mating surface of the pressure plate.

Might be something to check into.

 

I actually had the same response as "thesmogman" from my local shop. I had 171k on the odometer when I rebuilt my engine. I replaced the clutch/pressure plate with an Exedy unit and had the flywheel resurfaced with the step taken into account. I'm at 191k now and it still slips if I get on it, drives fine if I'm light on the gas. I got used to it so I stopped caring but if there's a solution to this I'd like to know. My car is a 94 CX by the way but the principle is the same.

 

The story (part III): Last weekend I went back to the shop (my own garage) where the car had been sitting since the previous weekend. It sat for five days. Friday night I decided to venture out and see what would happen. I figured if all else failed, a performance clutch would cure the slipping.

When I pulled out of the driveway, the clutch was slipping pretty badly as I went up through the gears. I seriously thought about taking it back and pulling the trans off again. But instead I kept going. I went down a country road. I would stop completely and then take off and shift up through the gears. Then stop again and repeat. I did this probably two dozen times. I tried a few different ways of shifting too; matching/mis-matching the revs to the wheel speed. I even tried letting the clutch back in after a gear change without any throttle at all. The car would kind of jerk, and I knew the clutch disc was really getting a workout.

The first few times I stopped/started, the clutch was slipping really badly. But it slowly got better and better. And after about a half an hour to 45 mins. of the “stop/start workout,” I could shift through all 5 gears with no slipping if I did it very carefully and matched the revs well.

I took the car back to the shop and parked it. The next morning on Saturday I had to run a few errands, so I figured I would take the CRX. It didn’t slip once during the trip. I took it to the mall parking lot and did about 15 minutes of the “stop/start workout.” I took it home and it sat for about 6 hours before I took it out again. The clutch slipped once in 1-2 gear change as I was accelerating from a stoplight on a hill, but it quickly grabbed, and I didn’t have any problems after that.

On Sunday I took it back to my apartment without any problems. I now feel fairly confident that the problem has solved itself. I still have a ways to go for the ‘500 miles of city driving’ break in. Most of my daily commute is highway, so I’ll probably drive for 1,000 miles before feeling safe to drive a little harder.

Moral of the story: if your new, correctly-installed clutch is slipping, let the car cool off. Then take it out and try doing a stop/start routine as I did for half an hour. Let it cool well, then do more city driving. It seems like my clutch needed some heat cycles to get worked in, before it started grabbing well.

Also, ALWAYS resurface the flywheel. Better yet, REPLACE it. I’m doing okay with a remanufactured flywheel on my completely stock CRX Si, but I was not impressed with the machining work.

Read this too for an explanation of flywheel hot spots: http://www.sandyblogs.com/techconnec...d-chatter.html

If you look back at the pictures, you can see where my old flywheel had some hot spots. I don’t know if continued driving and a “stop/start workout” on the first clutch would have solved the problem. But I do know that the first new clutch was slipping worse than the second new clutch. I kind of doubt that it would have fixed itself; so I think replacing the flywheel was the magic trick here.

I will finish the break in and report back, but it will probably be several weeks.

 

hmmm, well good to hear its working correctly now. that sure is strange though, i've never had a new clutch act up like that.

 

hey i have an 88 crx si just got a zc single cam rebuild and bought a whole clutch kit which is exedy a stage 1 an got the exedy flywheel. for some gay reason the clutch dosnt match up with the holes the exedy serial number for the flywheel is hf501 an the clutch kits is #08802 anyone knows then let me know