Clutch Issues

[wickwear]

92' Prelude Si manual transmission
What are the signs of a worn out clutch? When I try and put the transmission into 5th gear it sometimes doesn't engage properly and although the stick is in the 5th gear position, the clutch isn't engaging and I am in neutral. This recently started to happen within the past two days. About a week and a half ago, when ever I was in 3rd and 4th gear I could hear a high pitch sound. It sounded like the wind was rushing by (a high pitch whistle). This would happen in 3rd and 4th gears and now it happens in 5th too. Any suggestions? I want to say that the clutch was replaced about 50,000 miles ago. Thanks.

[spiffyguido]

Your clutch may be worn out, especially because you've already got 50,000 miles on it.

5th gear puts the wheels at the greatest mechanical advantage against the engine, so if a clutch is wearing out, it usually becomes noticeable in 5th gear first. Does the car feel like it struggles to get moving in other gears as well? Does it feel like all of the power isn't getting from the engine to the wheels?

[wickwear]

I just looked at my records and I think I have more like 40,000 miles on this clutch. Thanks for the response Spiffy, to answer your questions, I haven't noticed any diffenerce as far as the other gears struggling and it feels like power is getting to the wheels just as before. On my drive home from work today, it took more effort to finally find 5th and get the clutch to engage. All the other gears are fine. Other than the clutch do you think there is any other problem?

I'm pretty sure it is the clutch but I am trying to get an idea of how much this is going to cost before I become 100% committed. I've see a lot of you guys say that the extra cost of the Honda parts is worth it, how much will a new clutch cost approximately (without any labor)?

Thanks again guys.

[spiffyguido]

Honda parts are always worth it. Have a check over at http://www.hondaautomotiveparts.com for a cheap deal.

Also, for aftermarket clutches, Amazon sells Exedy (from Japan, good stuff) on the cheap with free shipping. This is the OEM one for your car:

EXEDY KHC03 OEM Replacement Clutch Kit
Note: As an amazon associate, I earn from qualifying purchases.

If you're looking for a Stage 1 clutch (which I wouldn't really suggest for everyday driving) then the Exedy part for your car is 08805. Probably also available from Amazon.

I will say though that if you don't start having trouble in other gears soon, you may want to double-check things to make sure it is in fact the clutch. Not being able to get in gear could be caused by a bent shift fork or maybe the sychro is ravaged (in which case the gears would grind when you tried to get into 5th).

Labor will be steep. Are you going to do it yourself?

[wickwear]

So here is an update. Within the past couple days the problem has got a lot worse even to the point that I am going to stop driving her until I get her fixed. On a drive back home today I could hear some serious rattles and it was when I would occur in any gear when I would take my foot off the gas and let it coast while still in gear. By the time I got home I could hear the same sound even with the car in neutral and the clutch released (engine is just idleing). It sounds like something is moving around in the clutch area because when I press the clutch the sound goes away. (I feel like I am not doing a very good job at describing this.) I am pretty sure that it is the clutch that is causing the noises/issues. Will I do it myself? I would love to, but I am afraid I will get lost in there and end up doing more damage than good, so I am trying to get ahold of my mechanic. Is there anything unique to the Preludes that I need to know about in regards to replacing the clutch? Thanks for the link to the part on amazon. My Prelude is a daily driver so I think I will stick to the one your suggested.
Thanks for the help guys.

[spiffyguido]

The clutch job is bog standard, as far as clutch installs go. There's nothing special going on with your Prelude's clutch system.

Some people will suggest that it's a good idea to resurface the flywheel when you do the clutch. I'm still undecided about whether this is always required. It depends on wear. Let your mechanic decide.

Regarding the noises you're hearing, it's hard to know for sure what you might be hearing. You might be hearing the sound of the rivets or springs in your clutch getting loose, or maybe some metal is contacting the flywheel. Either way, I think it's high time you got in there and checked things out.

Since your mechanic will have to pop your axles out to drop the tranny, it's not a bad time to replace the axle seals on the transmission housing. These cost about $15 each and do wear out with time causing annoying transmission leaks. Not a bad idea to get them changed while the transmission is dropped. Have a look at the integrity of your CV boots and CV joints as well.

I think we're all interested to see how this works out. Let us know what you find.

[wickwear]

Here is an update, I ordered the previously suggested clutch kit and had my mechanic install it for me. He mentioned that the old one needed to be replaced and he put all the used parts in the trunk for me. When I finally got it back I noticed that the same sound as before was happening. I drove it a couple miles and still had the rattling sound and high pitch whine. So I took it back to the mechanic and asked him about the sounds and the grinding of 5th gear. He looked at it again and the next day I picked it up. He said there was very little oil in the transmission which he suspects has resulted in a bad bearing in the transmission and that is what is making it a little more difficult to shift. He said the grind as I shift into 5th is caused by a bad synchro and the very low transmission oil just added to the problem. He added the correct amount of oil and adjusted the clutch a bit and now it is a lot quieter.

I did some research online and found that a lot of preludes have had the 5th gear synchro go bad, so if that is the case, I'm fine with that.

However, I took a look under the hood this weekend and I still have some questions. When I have the car running, in neutral and the clutch pedal is not pressed, It sounds like my flywheel is making some contact with the clutch. There is no noticeable lurching forward but when I start the car (the clutch pedal is pushed in) and then release the clutch (while in neutral), my rpm's drop about 200. If i push the clutch in again the rpms go back up. So to test this I decided to lift the front wheels off the ground and then start the car. Sure enough when the car is in neutral and the clutch released the wheels spin forward. Here is my question:

Should there be contact made between my flywheel and the clutch to cause the wheels to spin even when the car is in neutral and the clutch not pushed in (when up on floor jacks)?

Isn't the clutch supposed to be completely disengaged when the car is in neutral no matter if the clutch is pressed or not?

I am starting to think that my clutch slave cylinder is bad/going bad. With my hand, I can easily push the release fork into the slave cylinder and the slave cylinder does not rebound back to the original position. My mechanic said he bleed the clutch, so I don’t think it is an issue of air bubbles. Should there be more resistance from the slave cylinder? See the pictures on how bad the slave cylinder is.

From what I’ve researched online about the clutch system, the problems seems to be around the master and slave cylinders. I’ve examined the clutch master cylinder and I’m a little suspect but feel that I should first start with the slave first. There is a little evidence that the master is or has been leaking but the slave is much easier to change out. What do you think?

Sorry that this is such a long boring post but I would appreciate any help.

[spiffyguido]

Hi Wickwear,

First of all, thanks for writing back to tell us all how things went with the repair. It's great when people check in.

Regarding the 5th gear synchro, I too have read that a lot of people have this problem. It's the case on my Prelude, and my mileage is low. I think it's a common problem. Don't worry about it. Just use double clutching to compensate for the weak synchro.

No matter what gear you are in, even if the car is in neutral, when you release the clutch the clutch and flywheel meet and the engine begins turning all the gears in your transmission. The fact that your RPMS drop in neutral is just caused by the fact that once the clutch is released, even in neutral, your engine now has to cope with the added strain of rotating more mass because it is spinning the shafts and gears in your transmission.

It is normal for your wheels to spin when the car is off the ground. All manual transmission cars likely would exhibit this behaviour. Here's why:

There are several shafts in your transmission with gears on them. There is an input shaft that takes power from the engine and brings it into the transmission. When you drop the transmission you can see one end of the input shaft because it pokes out of the bell housing and fits into the splines in the clutch pack. The input shaft feeds power to the layshaft, which is really just a shaft with some gears on it. The gears define your drive ratios. Each of the layshaft gears is always turning a gear on the output shaft. So, all the gears in your transmission turn at all times. The gears on the output shaft however are not fused to the output shaft itself. They spin freely on bearings. In order to be engaged, a collar (which is fused to the output shaft) has to be slid into and locked against the output shaft gear to transmit the engine's power to the wheels. The reason that your wheels spin while the car is off the ground is that even though the output shaft gears are on bearings and not engaged, there is still enough force being transmitted through the bearings to spin the wheels slowly.

As my description is likely rubbish, have a read here as well: http://auto.howstuffworks.com/transmission2.htm

The clutch does not disengage when you put your car in neutral. The transmission and the clutch operate completely independently of one another. The only way to disengage the clutch is to push the pedal.

The picture of your slave cylinder looks like it may be in rough shape. Most concerning is the fact that the boot is clearly broken and so the interior of the cylinder is probably ravaged. They're not expensive, so it's probably a good idea to replace it. Honda used to sell a rebuild kit for them, but I'm not certain you'd be able to get one now. In my experience, the slaves wear out faster than the master cylinders, so it's a good place to start.

A bad slave or master cylinder won't really make the clutch easier or harder to push. That always comes down to the pressure plate. If your slave or master cylinders are bad, you'll notice it more when you try to change gear as gear changes will be harder.

If your master cylinder goes bad, you'll know because they often leak into the inside of the car. I don't see any indication of fluid loss on the picture of the master you sent. It's probably fine.

[wickwear]

Spiffy, Man that was an awesome explaination, I really do appreciate the time that took to educate me. I'll be picking up a new slave MC and will probably replace it next weekend. I'll update after.

Hey one more question, you mentioned double clutching to compensate for the weak synchro; this may be a silly question, but what is double clutching and how do you do it. I have tried somethings that seem to help compensate for the weak synchro, but I'm not clear on the double clutching.

Thanks again.

[spiffyguido]

'Double-clutching' is a term from car racing. Race cars don't always have synchros because a race car engineer will see a synchro as non-essential to the car's ability to go fast. A synchro is therefore 'useless extra weight' on a race car and will be thrown into the trash faster than you can say "I stuffed a car on the corkscrew". Double-clutching in race cars without sequential transmissions is therefore a requirement to drive them....here's why:

As far as a transmission is concerned, synchros are really there more as a convenience than anything else. A synchro's function is to help the dog teeth on the drive collar mate up with gear the driver wants to select. They help the engine revs match up to the new gear ratio being selected. The effect is hard to detect when you're driving because while the clutch is depressed during the gear change you won't feel the impact of the synchro through the engine. Inside the transmission though, during the shift, a synchro is hard at work accelerating or decelerating the gears and layshaft in your transmission so that the dogteeth on the drive collar can lock into the newly selected gear.

A well trained driver doesn't require such niceties to get a car through the gears. Any driver worth their salt will have the gear ratios of their car etched on their mind and will automatically use the throttle to get the revs where they need to be for the next shift. It's not hard to do, and if you think about it a bit, you'll find yourself doing the same.

On a production car, using the throttle to match the upcoming ratio is easiest to do on a downshift. Imagine yourself slowing down in your car. You need to come into 3rd gear from 4th.

A normal driver will do the following:
-Depress the clutch
-move the gear shift from 4th gear to 3rd
-release the clutch.

A good driver will do the following:
-Depress the clutch
-move the gear shift from 4th gear to neutral
-release the clutch and blip the throttle to bring the engine speed up to the new ratio while making the gear change to 3rd
-depress the clutch
-move the gear shifter from neutral to 3rd
-release the clutch

A race driver will do all that a good driver does, but will do it while also heel-toeing on the brake (applicable only to clutched cars), looking in their mirrors, and in the case of cars that stop really quickly, they'll be mostly blind during the process (Formula 1 cars stop so quickly that the driver's eyes deform from the G-forces and it temporarily impairs their sight).

This is why it's called 'double-clutching' because the clutch is depressed twice during the gear change. In actual fact, you don't have to depress the clutch twice, it just helps the engine AND the transmission come to the new revs required to match up the drive collar. Without the double clutch press the engine speed can be matched, but the internals of the transmission will still be spinning at their leisure. Race car mechanics will also point out that a single clutch press leads to parasitic loss in the transmission because the engine's power is being wasted for microseconds and isn't translating into motion where it is needed most, but that's splitting hairs.

In a production car, double clutching on an upshift is harder to do because production cars are universally equipped with very heavy flywheels which make the engine revs fall slowly when the throttle is released. This makes it hard to make a fast upshift using double clutching because you have to wait around while the revs fall. Contrast this to a race car which typically will have a very light flywheel; when the throttle is released, the engine revs dive FAST.

In your case, to make the change to 5th gear, you will depress the clutch, move the gear shift from 4th to neutral, release the clutch, coast for about a second to let the engine revs fall, depress the clutch, move the gear shift from neutral to 5th, release the clutch. If you've judged the target revs correctly, the synchros won't have been needed to complete the shift smoothly and you won't get any buzzing sounds from the dog teeth as they match up. Trust me, if you practice this for a little while your shifts will be as smooth as butter.

As an added bonus, driving in this manner is better for your engine, better for your clutch, better for your dog teeth and better for your synchros. This is because if you are matching engine revs to the gear ratios then the synchros never have to eat up any unnecessary forces that the wheels chuck into the transmission when gears are changing and the engine won't have to get spun up aggressively by the wheels when the clutch is released.

But don't listen to me, let's watch the master himself at work. Senna uses double-clutching several times (though not exclusively) both on up and downshifts in the following video.

http://www.youtube.com/watch?v=8By2AEsGAhU

Don't know who Senna is? You must: http://www.youtube.com/watch?v=aNmqn3heGgE

I hope this helped. It's a tad hard to explain, so if I've only confused you more, ask some follow-up questions.

[RedRacer]

Great textual description of double-clutching Spiffy! Very well done. And an excellent video link as well as to how it is is done in a "normal" car.

I love driving the G like this, but it's not as forgiving as the Prelude so I don't do it as often.

Just scanned the above posts and wanted to add comment without having read every word ---- The 4th Gens do have a known problem with the synchros going into 5th gear. I think I even once saw a TSB and recall notice on it.

Also, just to add, had a friend who had what we thought was a bad clutch -- turned out it was a bad seal that was allowing a bad oil leak to breach the clutch plate and cause it to slip. Cleaned things up, put everything back together and it drove and shifted like brand new.

[wickwear]

Sorry it been a while guys, and thanks for sharing your knowledge. Since I had the clutch replaced I've improved on shifting into 5th gear. Now I have the task of teaching my wife how to drive a manual transmission and (yea I know) unfortunatly it is on my Prelude. Our other car costs twice as much to drive and I'm tired of paying for so much gas.
Since the clutch replacement, I've replaced the boots/bellows on my Rack and Pinion and at the same time the outer tie rods. I have since noticed that there is a moderate oil leak dripping from the transmission housing. I don't think I noticed it before because I was leaking powersteering fluid from my rack and pinion so bad. So I'm wondering if I am having something similar to what RedRacer mentioned at the end of his post. I'll try and take a closer look this weekend, I'll let you know what I find.

[spiffyguido]

Most important will be to determine what type of fluid your losing. If it's oil from your tranny then you probably have a bad axle seal. If it's engine oil then you need to be worried about he condition of your crank seal.

My bets are on the axle seals.