Clutch Problem - RX-8

[Casey]

Had a track day at Snetterton cut short last week    and had to resort to my recovery company to get my car home 

First session on track, after about 15 minutes (just about to do a cool down lap), all going superbly, no signs of any issues, and then I struggled to engage 4th gear. At next gearchange I couldn't select any gears. Managed to coast safely of onto the grass and then managed to crash into 2nd gear and limped off the circuit. 

Symptoms:
1. Noted a central trail of fluid (felt like brake fluid) on the path the car took into the pit garage. Unable to see where this was coming from exactly and MAY have been from other cars sharing the garage.
2. The clutch slave cylinder actuator was moving with the clutch depression, but probably not as much as it should (short throw).
3. Tried bleeding slave, but couldn't get all the air out (suggesting air coming in from somewhere). The above suggests a slave, pipe or master seal leak?

Car 11.5 years old, 76k, with a hard life on track. I know the slave cylinder (and flexi-hose) is a potential weak point as I've replaced two failed salves on my RX-7 FB's (a 5 minute job as they are soooo accessible!) Here's a video of what happens when the clutch pedal is depressed, which makes me (also?) suspect the clutch release bearing.

UPDATE: I got the passenger side as high as I could and managed to crawl under to take a looksee. Here's what I found:

Starter motor off - just the usual black dust, all dry in there and no "fluff"


A minor amount of "stuff" (friction material?) was around the starter motor housing:

I decided to take off the clutch slave - what a pig that was to "break" the bolts free    thank goodness for some advice from Aston at Essex Rotary to get a set of flexi ratchet spanners for the job. I have a Halfords about a mile from me and they had an "Advanced" set of 9 spanners (with lifetime guarantee)  - £80 reduced to £40 - bagged a bargain by popping down there before starting the job 

Slave bore, piston and seal in good nick, but I'll change it for a new unit anyway (only about £40 and I don't want to do that job again in a hurry!



I took the clutch flexible hose off to check - seems fine, no leaks apparent, tested it with a airline, but I'll replace it with a steel braided one anyway.


I now think the issue is with the the release bearing. It would explain the noise on trying to disengage the clutch. I don't think the clutch friction plate is the issue, as I managed to "crash" into 2nd gear on track and drive off normally with no slipping clutch, the car felt normal to drive once a gear could be selected.  Whatever, I've concluded the gearbox has to come out, so I'll be avidly reading up manuals and guides before tacking that next week.

[Casey]

Interesting - this info was posted up on RX8OC:

"That video clip sounds a lot like mine did before the release bearing failed although mine was not so loud

Also the bits you found look a lot like what Essex Rotary found on separating my gearbox



Although mine did actually disintegrate"

[Casey]

Those black bits that came out of my starter motor aperture do suspiciously look like disintegrated bits that release bearing?

I understand these bearings are manufactured in two basic types, "all metal" and "part plastic". The above disintegrated bearing was part plastic and had done less than 20k miles. Interesting, my bearing was replaced at the same time as a gearbox/clutch change, just short of 20k miles ago. What's the betting my bearing is "part plastic" and has failed? The original OEM bearing had done 56k and was still OK when replaced as a matter of course when the gearbox failed (long story, "wrong" oil spec used, synchros failed as oil to "slippy).

Another RX-8 owner is popping over to my place  next week to help with dropping the box 

In the meantime, have got my car up as high as I can on stands and have squirted WD40 liberally on various bolts.

- that's KIMI 1, RX-7 FB, in the other garage space, under the cover 




The car looks very close to the right hand wall in that pic    Camera abberation, I can walk down there easily and jacked the car up in the space available without trouble.

Extra safety supports under front wheels - some old FC alloy wheels

[boosted]

blimey...thats a very large dust cap you have Casey 

[Casey]

:-) that's the Tyrepal TPS sensor - brilliant to monitor live tyre pressures on track, and only £99 for the set.

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[Casey]

I spent a few hours in the garage today and made steady progress, but with two niggling issues due to the inevitable rusty nuts/bolts   

Removed gear gaiter and shift lever.
Removed rear and mid cross members (one bolt found to be missing!)
Disconnected cat sensor.
Removed cat.
Removed Manifold bracket and used a block of wood to support manifold onto front cross member (I guess this supports the back of the engine from dropping when the transmission is removed?).
(The bolt into the manifold sheared, so that needs drilling out and re-tapping  )
Removed PPF heat shield.
Loosened all 8 nuts (and the one bolt) on the PPF
(The splines on one of the pair of top bolts in the diff stripped the splines in the diff housing - the bolt and nut are now "trapped", as the nut stuck on last rusty part of the thread. May use an air cut-off tool and replaced with a nut and bolt.)
Drained gearbox oil; it looked disgustingly grey (it's not been in very long!) but hardly anything on drain plug.
Disconnected gearbox wiring, 5 connectors in all (noted the outer insulation on the O2 sensor loom has melted through  , but wire insulation intact. Need to re-insulate).
Block of wood in place behind diff to stop it rotating downward when prop shaft removed.
Cracked all 5 bellhousing to engine bolts - easier than I thought this would be with multiple extensions 

Already done before today:
Disconnected battery.
Removed starter.
Removed the slave cylinder.

So, once the last PPF bolt is sorted I thinks it's:
Support transmission
Remove PPF
Mark and remove prop shaft (putting it somewhere safe!)
Drop the gearbox

Tractorboy on the RX8OC has very kindly offered to pop over on Wednesday with his low transmission jack and some other tools to complete the removal   

...look to see what has happened in the bellhousing....

Any step I've missed?

[boosted]

Pat on the back fair play that man. Only thing i can of is whilst gearbox off changing gearbox output shaft oilseal...i got 1 from Clive.

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[Casey]

  Thanks Jon, I'll check the seal for signs of leaks. How easy was it to change the seal?

[boosted]

Well easy pick out and use a socket to knock in...i caught mine and torn it when pulling prop out.

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[C J R]

Those gearboxes are HEAVY, so good idea using the transmission jack (I bought one ready for my next box change). I would suggest its still a two man job pulling (disengaging) the box input shaft from the clutch.
Make sure any hoses or wiring around the top of the bell housing are taped out of the way. The tend to get trapped when you refit the gear box.

Good luck.

[Casey]

^^ Thanks for the tips guys 

Success    Gearbox dropped (not literally  )



Thanks again to tractorboy for popping over today to give me a hand to drop the gearbox, using his transmission scissor jack made it a doddle  :thumleft: Ian.Mothersole dropped by to return my extendible  socket wrench, so at this point we had 5 rotaries at my house (KIMI 2 under the cover and KIMI 1 behind the closed garage door...



A few minor issues were encountered with dropping the gearbox;
- the four nuts holding the propshaft onto the diff were INCREDIBLY tight and took a 600mm braker bar to crack!
- We had to use a grinder with a cutting wheel to remove a "trapped" nut/bolt holding the PPF onto the Diff


tractorboy did a great job in using his cobalt drills to drill out the remains of the sheared bolt in the manifold bracket and retap for a larger M10 bolt.

Once the gearbox was off, the suspected failed release bearing was confirmed as the problem:


The inner and outer were completely seized due to a collapse of the bearing.

Everything else looks OK, but I'll do a clean up of some of the removed parts before they go back onto the car:


I have a new clutch, bearing, clutch master, clutch slave, clutch braided line and reversing switch on order from MRP which should arrive on Friday

[re japi]

I love that front of the house pic!!!  But that one car doesent belong there 

[Casey]

^^ I was expecting someone to comment on my wife's (honest  ) H***da 

[boosted]

Honda Jazzes have 8 spark plugs ! Good work mate...dont forget to grease the pilot bearing.

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[Casey]

The reassembly began today - tractorboy has kindly offered to come over on Wednesday to help with the "heaving lifting" onwards.

So today, cleaned the bellhousing, greased the guide collar and fork to fit the new bearing:


Here's the new and "old" (3 years old!) reversing switch. The old one had bubbled badly with the heat from the CAT - there was a hole in the potting compound, so not far off leaking:


So, set about constructing a heat shield from an old USB hard drive case:


A couple of coats of VHT silver paint (the notch rests on a gearbox "buttress" and stops the shield from rotating when tightening the sensor):


Fits great, hope it seals OK when Oil goes in (I've used an ali crush washer under the shield) 


The heat had also melted through the O2 sensor harness cover 


Sorted with an underlayer of self amalgamating tape and a top layer of aluminium tape:


Replacement M16 bolt/washer/nut for the PPF/Diff to replace the one we had to grind off:


Decided to tart up some of the really rusty bits that we'd taken off with a couple of coats of black POR15:


The "before" shot"


Lastly, the clutch  and pressure plate are fitted and torqued up using tractorboy's clutch alignment tool. A little grease also applied to the pilot bearing, which seemed to be in good shape.

Hopefully we can finish the job on Wednesday and get her back on the road