Clutch getting heavy and vague after 45mins-1hour???

[havoc]

I've had an incipient problem since last summer's Euro road trip, which isn't going away and if anything is getting more noticeable...

- From cold, the clutch is fine - I often get a 'screech' on pulling away (which I'm thinking may be the release bearing? Any other suggestions?), but I always have and it's not caused any problems...yet.
- For short-journeys, the car is fine.
- BUT...use the car for a while, and the pedal starts to get a lot heavier, and in operation starts to feel a bit more vague. It still works, but it doesn't feel quite right or very pleasant to use.

Started to notice it when stuck in a M-way traffic-jam (stop-start for ~1hour) in 30-degree C heat after driving for 4+ hours already...still had >100 miles to go and got rather worried whether we'd make it to the hotel.
(Actually, first noticed it a week earlier when in traffic at the end of a long and fun blat over the Alps, but that was just the last few miles to the hotel)

I've since noticed this also happens after the car has been parked up in the sun for some time...so I figure it could be something getting too hot - slave-cyl seals???


Other info:-
- Clutch master cylinder looks fine, fluid level looks fine.
- Clutch slave cylinder was replaced 3-4 years ago according to the service records.
- Kaz had noticed a very slight weep of fluid into the driver's footwell when he inspected two years ago, but this hasn't persisted.
- Clutch is Exedy item fitted in 2007 at ~68k, so 34k miles ago.
- Engine bay cover is CF, not the OE item, so engine bay temps may get hotter than standard, particularly when stuck in traffic...or in direct sunlight, as above!


Cheapest I can see a clutch kit for is c.£1k (inc duty) plus shipping from the US, so even though the clutch has done a reasonable life, I'm not that hard on it (no idea on previous owners), would like to explore other options before changing it. But would also like to get it fixed before the summer arrives...

I've done a search on here and slave-cyl would seem a good place to start, if it hadn't been replaced a few years ago...is it possible it might not have been fitted properly?

Cheers all,

Martin.

[NSXGB]

Martin
Regarding the screech, your description matches a noise I had on spirited launches when I bought my car. I put it down to the release bearing too and it went when the new clutch was installed. Not conclusive that it was the bearing I suppose, but I'd put money on it.

Otherwise, has your clutch master cylinder reservoir got any black debris in the bottom, indicating seal breakdown?
If there was evidence of a clutch master cylinder leakage before, I think I would possibly start there. They don't usually get better over time and it's the only part you have no service records for, correct?

Has the fluid been changed recently? This can also be greatly affected by heat.

Might as well change the rubber clutch hose too if you end up changing your master cyl if it hasn't been done for a while....


If you do need a new clutch drop me a line.

[AR]

I was under the impression that master and slave cylinders should be changed together.

The noise does sound like the bearing.

Best of luck.

AR

[Kaz-kzukNA1]

Hi, Martin.

I think I understood what you are trying to say by the term ‘heavy’ but not sure about the word ‘vague’.
Are you referring to the changes in CL bite point or the CL Pedal feeling?
Any difficulties in selecting gears under cold/hot conditions or CL slipping under heavy acceleration?
By operating the CL Pedal with your hand, does it press down and go up smoothly even when you are having this ‘heavy’ and ‘vague’ feeling?


You may have multiple issues so please refer to the followings.

If you have CL hydraulic system issue at the master/slave cyl, CL hose, damper joint and/or hard lines, then you are very likely to experience difficulty in selecting the gear.
Basically, you are not disengaging the CL fully before moving the shift fork.

It seems that you didn’t notice any changes in the fluid level at the CL master cyl reservoir so very unlikely to be the hydraulic related issue for your case.
By the way, the CL fluid won’t get so hot compared to the brake system. One time, we had to use green tea instead of brake fluid in the CL hydraulic for emergency recovery to get my friend’s NSX back to the factory.

If the plunger of the CL slave cyl is not sitting inside the ‘pocket’ of the CL release fork properly, I think you will experience several issues even under cold/hot conditions.
You can access the slave cyl from the top (remove air box), the bottom (remove shift cable) or the side (remove tyre) and since it’s only held by the two bolts, you can easily check it without disturbing the hydraulic. Just apply good quality grease in the pocket of release fork on re-installation. You may struggle to insert the dust cover to the side of the GBox if you don’t have good access.

As a side note, please always replace CL master, slave, hose as a set. If you just replace one of them, it is very likely to accelerate the fatigue on the other two.

Since Exedy has patent in pull type CL cover design, you don’t use push-pull converter mechanism.
If poor quality grease was used on installation of the new release bearing (I hope it was replaced at the time of CL service) or the bearing guide got rusty, you will get ‘heavy’ feeling.
For me, release bearing, bearing guide, release fork, etc are 'must' items to be replaced when installing the new CL.

If your CL assy doesn’t slip under hard acceleration, you should be able to reuse it although not sure how long it will last.

At Honda garage, removing the GBox and replacing the release bearing and bearing guide would be around 4.7Hr labour charge so not too bad.

Based on your other post, seems like you are expecting new family (or possibly families - congratulations) so may be you want to save for the big day and I hope you can re-use your CL for another few 10K miles.

So, unless you can find something wrong outside of the GBox, I would recommend taking the GBox off and inspect the CL area before it causes further issues.

Kaz

[havoc]

Well, the 'are you sitting down' number from Honda was £1,903 fitted for the clutch. This includes the release bearing, but still... :ouch:

Slave cylinder is now £121+VAT + fitting and master cylinder £173+VAT + fitting. Unsurprisingly these are significantly more than the prices quoted on here by others from a few years ago (c.£50 and c.£100 from memory). HUK's 100% inflation plan at work again... :(

Hi Kaz, good to speak to you again - thank you for your kind thoughts! Re-using the clutch would be the best result for me at this time, certainly.
To answer your questions:-
- I think I had some problem selecting lower gears when the car was really hot in the traffic in Germany. Not repeated since in the driving I've done in the UK. My 'vague' comment was aimed at the feel of the pedal - I don't recall the actual biting point changing, but I lost some feel/perception of what it was doing. Haven't tried by hand - will next time I take her out.

- The clutch doesn't usually slip under hard acceleration - I've only had this once, on a 2nd-to-3rd change at 8k rpm executed more quickly than usual. In usual 'spirited driving' it's fine. So hopefully there's enough friction material left for another year or two... :fingerscrossed

- Green tea! That's a fantastic temporary-repair...also from what you're saying it doesn't sound like there's an issue with the hydraulic side of things (I had the system bled last year after I returned, just-in-case - that I still have the problem also supports it not being fluid-related).

- No issues at all from cold, so that probably eliminates slave cyl / CL release fork alignment.

- Release bearing - I'd be surprised if it was replaced - it's not a standard part with most after-market clutches so often overlooked by those who are unaware or trying to save money. I believe that is the noise I'm hearing and it will be changed the next time the bell-housing is removed.

- Bearing guide...now there is a thought...thank-you for that comment! (Do you know if the bearing guide is part of the standard Honda 'clutch kit' - I'm told it includes everything except the release bearing?)


So I'll be contacting one of the US Acura guys, see if he'll ship a pair of cylinders over here for a fair chunk less than £350. Good point on the clutch hose - forgot about that bit, agree it's likely to be tired...and I'll find out the prices for the rel. bearing and bearing guide too...those last two will be duplicated labour vs changing the clutch, but it might be worth taking the chance...4-5hrs on that and ~3 on the cylinders, plus parts would still equal no more than half the cost of a whole new clutch.

Ah well...she's been pretty reliable since Kaz did all his work in 2010, so I'm due another bill I suppose.

[Hagasan]

Well, the 'are you sitting down' number from Honda was £1,903 fitted for the clutch. This includes the release bearing, but still... :ouch:

Slave cylinder is now £121+VAT + fitting and master cylinder £173+VAT + fitting. Unsurprisingly these are significantly more than the prices quoted on here by others from a few years ago (c.£50 and c.£100 from memory). HUK's 100% inflation plan at work again... :(

Hi Kaz, good to speak to you again - thank you for your kind thoughts! Re-using the clutch would be the best result for me at this time, certainly.
To answer your questions:-
- I think I had some problem selecting lower gears when the car was really hot in the traffic in Germany. Not repeated since in the driving I've done in the UK. My 'vague' comment was aimed at the feel of the pedal - I don't recall the actual biting point changing, but I lost some feel/perception of what it was doing. Haven't tried by hand - will next time I take her out.

- The clutch doesn't usually slip under hard acceleration - I've only had this once, on a 2nd-to-3rd change at 8k rpm executed more quickly than usual. In usual 'spirited driving' it's fine. So hopefully there's enough friction material left for another year or two... :fingerscrossed

- Green tea! That's a fantastic temporary-repair...also from what you're saying it doesn't sound like there's an issue with the hydraulic side of things (I had the system bled last year after I returned, just-in-case - that I still have the problem also supports it not being fluid-related).

- No issues at all from cold, so that probably eliminates slave cyl / CL release fork alignment.

- Release bearing - I'd be surprised if it was replaced - it's not a standard part with most after-market clutches so often overlooked by those who are unaware or trying to save money. I believe that is the noise I'm hearing and it will be changed the next time the bell-housing is removed.

- Bearing guide...now there is a thought...thank-you for that comment! (Do you know if the bearing guide is part of the standard Honda 'clutch kit' - I'm told it includes everything except the release bearing?)


So I'll be contacting one of the US Acura guys, see if he'll ship a pair of cylinders over here for a fair chunk less than £350. Good point on the clutch hose - forgot about that bit, agree it's likely to be tired...and I'll find out the prices for the rel. bearing and bearing guide too...those last two will be duplicated labour vs changing the clutch, but it might be worth taking the chance...4-5hrs on that and ~3 on the cylinders, plus parts would still equal no more than half the cost of a whole new clutch.

Ah well...she's been pretty reliable since Kaz did all his work in 2010, so I'm due another bill I suppose.

Just to note, the slave cylinder is the same LHD or RHD. The master cylinder is not, you'll have to stomach HUK prices there I'm afraid unless Kaz can possibly help you out with one from Japan.

Re the clutch kit. As he commented, NSXGB (Simon) can very possibly help you out in that area? Combined with a potentially much better fitting price at say, Norton Way Honda in Letchworth if you are down that way, I'm sure you can save considerably on the £1900 you've been quoted.

Hope this helps a little...

Gary

[NSXGB]

I thought the master cyl was the same for LHD & RHD?

When I bought mine early last year from VTEC direct I think I paid £300 delivered for the hose and both cylinders.

[havoc]

Cheers Gary. I had noted Simon's post and will definitely drop him a line if it comes to it...I just wanted to find out what silly money HUK were after as much as anything, so I'd got a worst-case to benchmark. Master-cylinder - hadn't realised, thanks for the heads-up.

N-Way isn't a bad idea if I do end up with Simon's clutch, actually...good call.

[Hagasan]

I thought the master cyl was the same for LHD & RHD?

When I bought mine early last year from VTEC direct I think I paid £300 delivered for the hose and both cylinders.

Definitely sided Simon. Kaz told me so when he did my health check with him...... I got the slave & pipe from the US but P/N's were different for the Master....

[Hagasan]

Cheers Gary. I had noted Simon's post and will definitely drop him a line if it comes to it...I just wanted to find out what silly money HUK were after as much as anything, so I'd got a worst-case to benchmark. Master-cylinder - hadn't realised, thanks for the heads-up.

N-Way isn't a bad idea if I do end up with Simon's clutch, actually...good call.

No worries.


I can't predict what NW will quote now for labour only but ask speak to Bryan Smith if you call. They are happy to fit OEM parts sourced elsewhere. About a year ago now both Simon and I payed in the region of £430 all in....each!!

[havoc]

One further thought for the tech-minded - has the NSX got a clutch spigot bearing?

Thanks,

Martin.

[NSXGB]

I believe the spigot bearing is installed in the flywheel.

[Nick Graves]

Martin,

Remember this is a common issue on S2000s too.

It's most usually caused by boiling your piss - well, the urea grease that's supposed to be on the selector fork.

There's an art to unclipping the arm (having removed the slave cylinder) greasing & replacing it.

On the NSX, it looks like a bloody nightmare to get at! Maybe Kaz has a tip or two.

It could be a duff master cylinder, but that's only gonna heat up by a couple of degrees in use.

http://www.hondaoriginalparts.com/hpl/images_car/17SW001/imge/M__1300.jpg