By on December 3, 2015

 

clutch. shutterstock user Stomchai_Stock

TTAC commentator krhodes1 writes:

Hi Sajeev,

Here is one for you and the B&B: ’74 (more or less) Triumph Spitfire with a clutch issue. The clutch feels “sticky”, doesn’t release smoothly, and makes starting off in first a little challenging. Otherwise, the clutch works fine once you are moving.

A bit of background: the clutch and throwout bearing have about 20,000 miles on them. Clutch hydraulics were done 15+ years ago, maybe 25,000 miles. No leaks. Last year, the pivot pin for the clutch release fork fell out, I drove the car maybe 100 miles before figuring out what the problem was and fixing it. There didn’t seem to be any damage when I had it apart, so I just put it all back together with the pin replaced (by a bolt) and it was perfectly fine — for a while. Then the “sticky” started. It gets worse when things get hot, but pretty much normal when the car is cold or been driven at highway speed for a while. It gets much worse in in-town traffic.

Would a failing throwout bearing cause this? It’s not making any noise that I can hear.

And before the Prince of Darkness jokes start, this car is usually bulletproof. I have owned it for 19 years and it is as faithful as an old dog driven as a toy for a couple thousand miles a summer. I think the last actual issue was 5+ years ago when the 35-year-old starter solenoid gave up the ghost. Replacement was less than $25.

By the way, the infamous “328!” is still going strong. It just passed 36,000 miles and warranty ends in seven days. I’m not worried about it in the slightest — though I did have an inspection done by our best local Indy BMW shop, who sadly did not find a thing I could get BMW to fix!

Sajeev answers:

ZOMG, I occasionally see a 328i and my mind wanders to your 328! So much excitement, such easy laughs.

 

On to the Spitfire: I suspect the clutch lever is slightly bent and it gets worse as the parts heat up as tolerances get tighter. That forum thread suggests eyeballing the lever may not raise red flags and only replacement with a new one shows the problem. Or perhaps removing the lever, rolling the rod portion on a smooth countertop and keeping an eye out for wobble?

The replacement looks pretty cheap, and the other clutch components are too new/low mileage to raise an eyebrow. Especially if nothing’s leaking.

What say you, Best and Brightest?

[Image: Shutterstock user Somchai_Stock]

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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18 Comments on “Piston Slap: A Triumph Over A Sticky Clutch?...”


  • avatar
    bullnuke

    I don’t have a picture or diagram of the clutch fork arrangement (pivot pin in particular) but replacement of the pin with a bolt might be a clearance issue – was the fork a “loose fit” on the pivot pin and now a tighter fit with the bolt? Perhaps there was some slop in the linkage with the pin/fork arrangement to allow for thermal effects which has been tightened up too much by using a bolt. Troubleshooting blind from 1000 miles away but this reminds me of mechanical linkage issues on the turbine-driven feed pumps of my youth.

  • avatar
    Zackman

    I have nothing to add except what Sajeev has suggested, but if the photo above is your car, WOW! It’s a beauty! If it isn’t, you seem to have a pretty nice Triumph, too, according to your description.

  • avatar
    Cabriolet

    I do not like that statement of a pin being replaced by a bolt. The manufacturer used a pin for a good reason. Replacing it with a bolt could cause a problem. Heat, vibrations whatever could cause the bolt to become tight then again the bolt might be just a bit too large and start binding when the bolt got hot.

    Nice car. I owned a few English car over the years and fully enjoyed them. They had a certain charm. Mostly by the side of the road. Only kidding. I just purchased a Mini Cooper S and am enjoying the hell out of it. I know it is not an English car any more (German) but boy is it fun.

    • 0 avatar
      Carlson Fan

      “I do not like that statement of a pin being replaced by a bolt. The manufacturer used a pin for a good reason. Replacing it with a bolt could cause a problem. ”

      I have to agree. I know it worked just fine at first but when you change something like that and then start having problems a little later on that would be a red flag to me. I’d start with a new pivot pin. Seems like when everything heats up the metal parts expand, something binds and then you have your problem.

    • 0 avatar
      ExPatBrit

      I have a 76 Spitfire, this is a common problem .

      If the OP visited one of the more popular forums,they would be advised to replace it with a bolt.

      Actually you get a long bolt and cut off the threaded piece just use the shank and head as your pin. As long as you don’t flip the car upside down it won’t fall out.

      More likely the 15 year old hydraulics or the fork has damaged the pressure plate.

      The other thing to check is for excess thrust washer play. There are washers that act as shims to limit the horizontal movement of the crankshaft. If the washers break or fall out, the crank, flywheel and clutch will slide back and forth when you push the clutch.

      Clutch can be kind of jerky, fix this quick it will total the block. There are special aftermarket washers to prevent this.

      • 0 avatar
        krhodes1

        Yup, this is the common fix. The bolt is the same diameter as the original pin, and fits the same. It just can’t fall out like the original. Dumb design. I’m sure they used a press fit pin in the first place because it was .5P cheaper! There is LOTS of slop in the arrangement both before and after – I have a spare tranny. Which is how I know the pin is the same diameter as the bolt.

        Not the thrust washers, when the engine was rebuilt 15 years ago they were pinned in place by the machine shop – also a common upgrade. And there is no movement of the crank – that was the first thing I checked.

    • 0 avatar
      05lgt

      Late to the party, but if the bolt shank is a close slip fit, heating makes holes smaller and shafts bigger… also the bolt head can bind, get the right pin in there. Most shifts are full in to full out clutch, only the start requires smooth modulation. If its not the pin, look for the binding that broke the pin and is now working to find the new weak link.

  • avatar
    sirwired

    Not really an answer to the OP’s question, but I have a related funny story to relate:

    My wife had a ’97 Wrangler, and one day she was driving it and the clutch pedal fell to the floor when she was trying to back out of the driveway. I got underneath the pedals and saw that the tiny plastic bushing that connected the pedal to the MC rod had fallen apart. I wrapped duck tape around the pin and she went on her merry way.

    This held for several months until it failed again, this time on her way home from work. She was horrified when I pulled up in the other car beside the road, duck tape in hand; she had no idea that was how I had fixed her car before.

    I drove it to the dealership right then to get a new bushing. It failed again on the way; I was stuck in a median in a busy intersection and couldn’t open the doors. I had to essentially do a shoulder-stand, in a Jeep with the top down, in the middle of evening rush hour in my work khakis.

    Of course, said bushing was not available as a separate part (had to buy a new MC), but I limped it to the local NAPA, where they sold me a snap-ring (which is what Jeep should have used to begin with) that worked great.

    • 0 avatar
      Zackman

      That sounds as ridiculous as a 1992 Wrangler we briefly owned. Good ol’ Chrysler decided that the best place for the clutch slave cylinder was inside the bell housing, where you had to unbolt the tranny and move it all back to get at the slave. Very thoughtful of them – and a very expensive fix, as I can’t do it myself. After the first time, and when it started going out again, I sold the thing, never to buy another Chrysler product ever again!

      • 0 avatar
        MBella

        That’s actually a common way of doing it, and better for actuating the clutch directly, and removes a failure prone lever from the assembly. It sucks when it goes out, especially since I’m sure Chrysler spent big dollars on the highest quality slave cylinder.

  • avatar
    jsj123

    I had a similar problem when I put a hydraulic clutch on the Falcon. I ended up replacing all of the plastic bushings with oil impregnated bronze bushings. It removed all of the slop from the linkage. I had to lathe them down to the right size, but I could have used the drill press as a vertical lathe.

    I also suspect the bolt. I used hardened pins with c-clips for the pivot points for the clutch pedal and master cylinder push rod.

    –Stephen

    • 0 avatar
      MBella

      Turn them down. Lathe is not a verb. (Sorry, grew up in a machine shop)

      • 0 avatar
        CoreyDL

        I’m lathe to admit you’re correct.

      • 0 avatar
        jsj123

        One of the downsides of being a self-trained mechanic, and crappy self trained metal worker is you often don’t learn the right words. And that is a bitch, because without the name of something you can’t buy it or ask for help, plus people don’t take you seriously.

        An example of this is the handle support spring on my jack broke. Unless I can name the spring, I can’t replace it. I may have to buy a new jacks for a 5 dollar spring.

        Long winded way to say “Thanks for the correction”.

        –Stephen

  • avatar
    MBella

    The lever being bent could be an issue. I would also check the rest of the clutch assembly, and make sure nothing is binding upp anywhere. Corrosion on the input shaft can cause the disc to stick a bit.

  • avatar
    krhodes1

    Thanks Sajeev!

    Interesting forum thread, but not the problem I am having. Looking at the pictures in the thread, he used WAY too small a bolt, and he was missing the sleeves – I’m not. I could see where that much slop would easily cause issues. Mine engages and disengages where it should, and doesn’t rattle, it just doesn’t engage smoothly.

    I’m really leaning toward it being a slave cylinder issue, so I am going to replace that first – I have a spare on the shelf, just need a rebuild kit. Of course, being a Little British Car, correlation does not imply causation – it could be a failed master cylinder! But if that doesn’t fix it, I’m just going to replace the lot. It’s all dirt cheap, and I can have the motor out and on the floor in an hour. Try that in a Miata!

    You will be happy to know that BMW managed to get the i right way around on my M235i! I put 3600 miles on it in Europe, just got it re-delivered a couple weeks ago. Makes a nice pair with the wagon, I think, but I might be a tad biased. So two Brits and two Germans in the garage these days.


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