27 replies to this topic

[tiger99]

As suggested above, use a ruler to measure movement of the top of the clutch release lever as the pedal is pressed fully, and held down for several minutes. You will do no harm at all to the release bearing.

And yes, there are many poorly manufactured hydraulic components about nowadays. You could have some of these but it is not established yet. If full lever movement is achieved and held, hydraulics are not the main problem.

If lever action checks out ok, next thing, in view of what we now know, or think we know (remote diagnosis is not always perfectly reliable), should be to remove the clutch cover and flywheel, and check clearance of the primary gear bushes. If it has had a certain proprietary floating bush, of completely the wrong material, fitted, pull it out and get it rebushed properly. Check that it spins freely on the crankshaft. You will need a new oil seal, the gear can, just, be pulled out, bringing the old seal with it.

No need to undo the transfer case just yet. That will only come if clutch and primary gear are both found to be ok.it makes sense to try the cheaper and easier things first.

[mini_pooper]

Hi all,

 

Making steady progress. A few more details and hopefully you can come up with some solutions?

 

- I have checked the entire clutch system for leaks and there is nothing to suggest this is the case.

- The clutch arm does not return by itself with the clutch pressed to the floor and held there for some time so the cylinders and seals are all fine.

 

This evening I re-adjusted the clutch to 15-thou on the stop (where 14-thou would go through but 16-thou would not, my feelers are only even numbers  )

 

Good news is that the re-adjustment had made the clutch smoother (the judder has settled a lot but still slightly present in reverse) and it seems to be easier to drive, though 2nd and 1st are still harder to engage as the "gate" is still there. Will inspect the gear linkage for that one before moving on with that issue.

 

The main issue now is point 5 in my initial post:

 

"Point 5) Sometimes, when trying to change gears, it is almost as if there suddenly are no synchros in any gear. You push the clutch in and the revs fall to idle (indicating the clutch releases), but then when trying to engage any gear, all you are met with is grinding like on a non-synchro first gear box when not double clutching. When this happens, not even double de-clutching and rev matching works (note that I don’t continue to grind the gears, I stop the car and do what I have written in point number 4 until I can get it back into gear)."

 

I experienced this again this evening when going from 4th to 3rd after the car had been going at 40-45mph for a few hundred meters. I noticed that this is exactly what happened last time I drove the car. Slowing from above 40mph and trying to gear down from 4th to 3rd will cause this and it will not fix itself until you come to a complete stop... If you stay under 40mph, no problems at all... Any ideas? Something in the gearbox not slowing down to allow gearing?

 

Looking through some old receipts from the first oil change after initial running in, I see the engine oil has likely had additional Zinc added to bring up the ZDDP content in the oil for running in, could this be the cause? 

 

This is the stuff -  https://www.summitra...a-159/overview/

Edited by mini_pooper, 20 June 2017 - 07:53 PM.

[nicklouse]

the Zinc content of the oil is there to help the gearbox and should be in all the oil you use. which is why people like Valvoline VR1

 

sounds like you have a sticky(dragging) clutch more than anything as it is unlikely that the syncros are worn out.

 

who did the clutch assembly and fit?

 

also note this from Spider

Was the Primary Gear replaced or Re-bushed?

[mini_pooper]

Will leave the zinc as it is for the time being then.

Sticky clutch sounds right from the symptoms. Was fitted by the guy who rebuilt the box and engine before I picked it up. The car has a lightened flywheel at the same time (probably should have mentioned this earlier) but any adjustment for that (if any) was done then.

I asked about the primary gear and he mentioned he did not do anything with it. Whether that means "did not check" or "did not need anything changing" I don't know, but with a guy with this many years' experience, I would assume the second one is most likely.

What do you think? :)

[Spider]

I think first it's best to establish what work has been done and what parts have been replaced.

 

The adjustments on the clutch are not that finiky where 1 or 2 thousands will make any difference at all. I don't ever in my life recall using a feel gauge here. I remove the spring, wind out the stop (with the fingers)  until there's no clearance, then wind it back in until there's a small clearance, just enough so the thrust bearing isn't spinning all the time.

 

But, I can't see this being your issue.

 

Likewise, I can't see any type of oil that you would have in there being the issue either.

 

I really feel given your description that possibly the ball on the clutch arm is cracked and / or broken or the primary gear is not free spinning on the crank. The latter could be simply from it being pinched by the flywheel or the bushes seizing to the crank and anything in between.

[mini_pooper]

Ok, next step then is checking the ball on the arm for wear or bending. Will check the rest of the arm at the same time at the wear points. If i see nothing there, next step is, I assume, remove the clutch housing?

Can the primary gear / bearing work be done without removing the clutch unit or does it sit behind this?

If it helps, the gearbox seems smoother when the engine is cold. Once warmed up, frequency of issues seems to increase. I've heard that a lightened flywheel with lower heat dissipation can cause a primary gear bush issue to become more noticeable?

[Spider]

Some of the primary gear checks and work can be done with the engine in situ and hopefully that will get you over the line.

 

That you say it gets worse when it gets hotter further suggests to me it's a Primary Gear issue, normally and in general the gearboxes shift better when hot.

 

I doubt that the lightened flywheel is giving grief in regards to heat dissipation.

[mini_pooper]

Got the roll pins into the eye under the shift lever this evening to replace the loose fitting bolts. Without starting and driving the car, it was definitely easier to find and get into reverse (needed less force and less movement to the right) so some of that slack with the bolts was probably too excessive. A lot more direct and precise now so definitely a small step in the right direction.

 

Until I drive it, it's hard to know if it makes the "gate blocking entry" on the way into first and second less of an issue. We'll see 

 

The clutch arm is off and positively (or negatively!) there is no wear in the arm itself and the ball on the end is round, polished and not bent out of position. There was plenty grease in the plunger. I have attached some pictures in case someone else can spot wear!

 

The pins look like they have seen better days and will be replaced once ordered and arrive in the post. They do show signs of wear (see attached picture). Will also replace the stubby arm to the slave, cheap insurance and looks better than this one that is a bit pitted along the shaft.

 

So tomorrow I'm going to try bleeding one last time in case a small (until now trapped) air bubble has decided to leave the master cylinder.

 

If nothing gives, I'm going to have to go inside the cover...   Can the plunger the arm sits in wear or would this not affect anything?

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[smurfomatic]

Silly thing, but check the clutch pedal itself and make sure the hole for the clevis pin is OK. Had problems with mine for ages until I did this and realised it'd worn by about 5mm - new pedal and all sorted!

[mini_pooper]

Silly thing, but check the clutch pedal itself and make sure the hole for the clevis pin is OK. Had problems with mine for ages until I did this and realised it'd worn by about 5mm - new pedal and all sorted!

 

No suggestion is silly 

 

I did a visual inspection with all the bits in place and lightly pushing / releasing the pedal to see if there was any free play before it started acting on the cylinder but all seemed good, maybe a little slack.

 

Will take another look with the bits out, but with the angle you need to persuade your spine into in order to get them out, it's not something I'm looking forward to   (It's not actually that bad, but still awkward!) 

 

- John

[nicklouse]

take the seat out, easy.

[mini_pooper]

take the seat out, easy.

 

Haha, even then, but sure makes it easier 

[mini_pooper]

Right, it looks like I have found the cause and the solution.    It's not at all what I expected but strange things do happen! It's a long post, but I think the full story is more interesting than just half of it!

 

The cause of the issue could be something that many should bear in mind for their own car as it was 2 common aftermarket parts that, combined, caused this problem. It could potentially be a bit of a dangerous combination if it prevents the clutch from freeing out when following other cars!

 

So, the story:

 

Having a look through the engine bay before bleeding the clutch last night, I had a poke around to check for leaks and that all the lines to the clutch were in order. That's when I spotted a potential issue. Being LHD, my car has the master cylinders on the opposite side of the bulkhead to the slave. This means the metal lines have to go across the engine bay and, on my car, these lines had been run along the crossmember, only 15cm away from the LCB Cooper tubular (not cast) exhaust manifold.

 

Tubular exhausts obviously get much hotter than cast exhausts since they are thinner material, to the extent where you can see them glowing slightly at night if the engine speed is high (about 2500rpm, not unusual when cruising). This obviously releases a lot more heat radiation onto nearby parts. The theory was a long shot, but with the next option being removal of the clutch assembly to check the primary gear, it was worth trying to see if the clutch fluid had been heated to boiling point by the exhaust while cruising at higher engine speeds. I have seen track cars with good, clean brake fluid turn black from overheating, so with this indicator in mind and expecting my new theory to get shot down with nice clean fluid coming out of the slave, I bled the system.

 

What came out? Fluid, black as the night (see attached picture!!). This fluid had boiled, even with DOT4+ spec. This is fluid that was new and had only driven 15 miles, so it was not an age issue. My theory could, at this stage, hold water! Was the clutch system experiencing the same as you get with brakes during brake fade, where the system just can't get enough pressure up to disengage the clutch because of boiling fluid?

 

So, bleeding until new, clear fluid came out and then topping up the master to the correct level, I wrapped the lines in fibreglass and foil insulation as used on electrical wiring that needs protection from heat. This was last night, and since it was getting late I decided to test this theory the next day.

 

Fast forward to today, I decided to test the car on a 75km drive to Lincoln with a large portion of the route being 50-60mph roads. This nicely simulates the conditions that have previously caused the gears to grind like the clutch is not disconnecting (high engine speed). Halfway into the journey and everything was running like a peach, no grinding like I had previously encountered before after only a few miles driving. I thought I had fixed it! Just after, the problem came back.... 

 

Stopping to inspect that the insulation from the day before had not fallen off, I immediately saw something I missed yesterday - the braided clutch flexi hose going down from the bulkhead to the slave cylinder. It was not just exposed to the exhaust, it is even closer to the manifold than any other part of the clutch system! "Is the boiling happening in the flexi pipe?", I thought to myself.

 

With no insulation left to protect the flexi, I looked around, and spotted a small corner shop about 20meters up the road. I picked up some aluminium cooking foil and wrapped the braided clutch hose in an attempt to reflect the heat. I did not have any clear tube to re-bleed the clutch (I like to see if air comes out!), but the rest of the trip to Lincoln went smoothly aside from one small grind. Seemed better, but not as good as earlier in the journey.

 

Nice day in Lincoln, too much ice cream, and time to get back home. Dropped by Halfords to pick up some clear tube and re-bled the clutch in the car park. That nice clear fluid I put in yesterday was now black. Bleed until clear, refill master and hit the road. Not a single problem all the way back, about 75km non-stop at 3000rpm. After insulating the flexi pipe from the exhaust heat and getting the bad fluid out, the clutch was smooth, responsive and felt like a perfectly set up system all the way home   

 

No air came out either time I bled the clutch, but there may have been small bubbles I didn't see caused by the boiling. Ether way, the fluid was black and had been exposed to way too much heat. 

 

It would appear that the combination of 2 aftermarket parts I have on the car have caused all the issues I have been experiencing - The LCB Cooper tubular exhaust manifold, and the braided clutch line from the bulkhead to the slave cylinder. Not sure if others have the same parts fitted on their cars, but it's worth bearing in mind! Maybe the black rubber flexi hoses are less susceptible to heat?

 

So, the issues are sorted and I'm happy. Next step is to move the clutch and brake lines so they run under the scuttle panel by the wiring loom instead of along the crossmember in close proximity to the manifold, and get an insulation jacket to fit over / around the exhaust manifold to keep the surrounding parts cool!

 

Happy car, happy man   

 

- John

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