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I sold my '00 Base Boxster and bought an '03 Boxster S with 63K miles, for more power. Not a race car but still fun to drive, problem is the clutch is really hard to push down. Not a problem in normal traffic but a serious nuisance in stop and go. I've seen posts that indicate a broken or worn "helper spring" or malfunctioning master/slave cylinder. Other posts say the clutch needs replacing (even though I have no idea how a worn clutch can cause this problem) and still other posts that say this is normal. I own a '06 BMW M Roadster with a high performance clutch and a Pontiac T/A WS6 with a high performance Spec twin disk clutch that I race and both have lighter clutches than the "S". My question is this... which is true? If it is normal, and I hope it isn't, how do I go about diagnosing the root cause?
The clutch assist spring is easy to diagnose. If the clutch pedal feels loose when completely released you most probably have a broken clutch assist spring. You can confirm this by going through the removal process. You need to insert a cotter pin in the spring shaft which ensures that the spring is held in one position and the ease it out. There are DIY guides on how to do it.
Do not know what amount of reduction in force the clutch helper spring provides. I would think to avoid keeping any pressure on the release bearing the spring is there to just help bring the clutch pedal up all the way. But of course you need to know and if the spring is missing to replace this and make sure it is working to see if that helps reduce the effort.
Also, be sure the brake fluid and clutch fluid are fresh. These should be flushed/bled every 2 years. I know from my Boxster experience letting this go 2.5 years had the clutch acting up and the shifting was affected. After the overdue flush/bleed clutch action was back to normal and shifting likewise. There was no noticeable change, good or bad, from the brakes.
At the end I know my 2002 Boxster clutch got real hard to operate. I'm sure this was due to a worn out clutch. The clutch was original and with 317K miles on it. Techs have told me a hard to work clutch one that requires more force than "normal" is one sign of a worn clutch.
How a worn clutch can be harder to work is as the disc wears the clutch hardware moves to adapt. But this can reduce the amount of leverage advantage the hardware has so it takes more muscle effort to push the clutch pedal down.
The amount of extra effort my Boxster clutch required was rather surprising.
Also, I was told the clutch can begin to develop a chatter/juddering engagement when it wears out, goes beyond this point, because the disc rivets begin to contact the flywheel. IIRC the amount of disc wear was 1.4mm. New the distance from the disc to the flanged side of the rivet head was 1.7mm. Worn out is when this dimension is at 0.3mm. Once that 0.3mm is gone the rivets make contact.
The rivets contacting the flywheel will wear a circular "groove" in the face of the flywheel that if not too bad and if the flywheel is deemed otherwise ok to use can be machined to remove. But it is best to catch the clutch before this rivet/flywheel contact takes place.
Thanks Macster. Just back from vacation after driving thru DC during rush hour on Friday. Could not imagine doing that with the Boxster since the clutch is waaaay too hard for 2 hours of stop and go traffic. Anyway, I checked my car and saw the "helper" spring was installed but I'm at a loss as to what it helps. With no pressure on the clutch pedal the spring is relaxed which I suppose keeps the pedal at the top of it's travel (as you said) and depressing the pedal stretches the spring which can only make the pedal harder to push down. So, I'm guessing removing the spring would have to help right?
Russpe,
I have the exact same issue on my 97 Boxster which I bought with 44K miles on the clock. When I test drove the car I noticed the heavy clutch feel but it operated just fine with smooth engagement and no chatter or other issues. I thought at the time it was either the assist spring had gone bad or the slave cylinder had gone bad. I negotiated the price some based on this issue and bought the car. The IMS bearing had been recently replaced by the previous owner at the same shop I use for my repair work. When I questioned the shop that did the work on why they didn't replace the clutch components when they were in there - according to them there was more than 50% of the life left in the friction material. I took out the clutch pedal assist spring and other than being very dry, it worked fine so I just lubed it and reinstalled it. Next I decided to flush the clutch / brake fluid which had no impact. Finally I started replacing components (yes I know wrong answer) so I replaced with new both the master and the slave cylinders which was a PITA and again no improvement. The shop believes the pressure plate springs are going bad - so a full clutch replacement is what will be required to fix it for me as I have pretty much changed out everything else. I have driven it another 6K miles and the clutch still operates perfectly other than the heavy pedal. I posted this issue on the PCA tech website and Pedro said some Boxsters are just like this and he knows owners who have gone 10's of 1000s of miles with this and still have a heavy pedal but a perfectly functioning clutch. At some point over the winter I will probably just tackle it and replace the flywheel and other clutch components to fix it - for now I really don't drive the car in traffic so I just live with it. On a twisty road I really don't even notice it much.
this was Pedro's reply to my inquiry (which was when I replace the master and slave cylinders)....
A stiff clutch pedal does not necesarilly mean that the clutch is done. I know many shops believe that, but in my experience most of the time a stiff pedal is due to other factors, such as a broken assist spring, a leak in the master or slave cylinders, and or a very dirty throwout bearing. I have had customers who's clutch pedal is very hard to depress maintain it for years without any issue to the way the car drives.
Can't tell you how much I appreciate your answer. Thanks!! Based on what you've said and done it seems the clutch (pressure plate/flywheel) assy must be the culprit. I know from personal experience that a high performance clutch usually comes with a matching, very stiff pressure plate spring. For all I know, the previous owner may have replaced the original clutch when replacing the IMS bearing (wishful thinking).
Question... when you serviced the helper spring did you test drive the car with it removed? If so, what did you experience? Also, did you find a DIY that details the removal/replacement procedure of the helper spring?
I'm sure there are some guys reading my post that are probably thinking I'm a weakling, that I should get an automatic or something and that a Boxster is considered by them to be a chick car. Well I'm not and it is just a super fun car to drive no matter if you're a man or woman. I think it was Top Gear that compared the Boxster S to the M Roadster. Watch the video... I did and bought one of each :-)
Russpe,
No I never tried to drive the car with the spring removed as it was clear once I removed it, it was not the problem so I just added some white lithium grease and put it back in. The worst part was getting my head under the dash - I would recommend removing the seat otherwise it is really difficult to bend yourself under there. I found a video on Youtube on how to remove it - I'm sorry I don't remember but a quick search should find the one I followed. I remember it being pretty easy to do once I got under there.
As for the hairdresser car concern, I own both versions - a Miata and a Boxster. That view is simply crap from small minded people - the Boxster is a serious sports car and of my fleet of toy cars (from 911 turbo to a couple of Shelby mustangs) the Boxster is my hands-down favorite for driving the twisty roads here in New England. I also love my Miata and drive both regularly. I wouldn't let that stuff get in the way of enjoying a fantastic car and the Boxster is a fantastic car.
Hey Russpe I just found your post since i was experiencing the same clutch issue. But what I wanted to say was that I noticed you said you traded up from a '00 to '03 Boxster S. Funny thing, a few years ago I traded down from '06 base Boxster that gave me nothing but issues to a '03 Boxster S 6-speed with 63k miles that hasn't really given me any. It just passed 100k and just took her from LA to San Fran and back on the scenic coast route Hwy 1. She never let me down during that 1,100-mile trip.
I just wanted to ask if you're as happy with your '03 as i been with mine. All the best! - Cisco Cali Hwy 1 from LA to SF. 'E' ticket ride all the way! : )
07-03-2019, 09:48 AM
2003 Boxster S heavy clutch
