Help! What's wrong? Tranny or clutch?

[Mike]

Just took the new Bug Eye at around the block for a spin. The transmission after 2 two miles would not shift, It would not allow me to get in or out of gear without forcing it. Grinding sounds going into and out of the gears. After I shut her off for a while, the problem seemed to go away, At least for now. Could this be a clutch or tranny issue? I'm novice at these sprites and a new owner. You help is much appreciated.

Mike

 

[tdskip]

Hi Mike - I'm not an expert but to get a thread started I'd suggest this kind of sounds like a collapsed clutch master cylinder line...

Also a good idea to start with the basics, have you check her transmission oil level? <span style="font-weight: bold">Unlikely</span> to cause the symptoms above, but it should be done anyway and will tell you if you have shavings in the gearbox. If you, or there is a lot of brass shavings, that might point to syncros or the gears themselves.

 

[bthompson]

Sounds like a clutch hydraulic problem I used to have. Have you noticed any leaks around the master or slave cylinders? Does the pedal feel increasingly spongy or ineffective the farther you go? My Midget used to do the same thing to a lesser extent. Within about ten miles, the engagement point would get closer and closer to the floor, until it would hardly shift at all. Oddly, it didn't leak much at all. Letting it sit would 're-set' it. A slave cylinder rebuild, and flushing and bleeding the line, is what did the trick for me.

 

[BugEyeBear]

1st Check your clutch fluid level.

2nd Check that the clutch lever on the trans is moving when you push the clutch pedal down.

3rd Check that the trans stops spinning when you push the clutch pedal down. (You should hear a reduction of trans gear noise.) If the trans gears keep spinning your clutch is either out of adjustment, OR you're not getting enuf travel at the slave, OR your pilot bushing/bearing is bad, OR the disc is sticking to the flywheel & pressure plate.

<span style="font-weight: bold">Make certain that it isn't a clutch problem before you tear apart the trans.</span>

AND as mentioned above check the gear oil level, AND gear oil type. (IF the gear oil is too thick it will tend to be hard to shift when cold, if too thin or low it will tend to grind, esp when hot.)


I had a Datsun Pick-Up in the 70's that started grinding and was hard to shift, especially when down-shifting. I assumed that the synchros had gone bad SO I removed the trans & sent it out to be rebuilt. It had a fairly new clutch, so I left this alone when I reinstalled the rebuilt trans.
Wouldn't you know, it still wouldn't shift right! :madder:
SO I pulled the trans again & put in a new clutch disc, pressure plate, & throw-out bearing. Reinstalled the trans & soon discovered that the S.O.A.B. was STILL GRINDING!!! I was losing it now!!
Turned out the problem was a worn pilot bushing, which cost me less than $5.00 to replace. (OF COURSE I had to pull the trans & clutch again to gain access....)

Moral of this story: replace the little inexpensive parts before you invest in an expensive rebuild!!
(Moral could also be, do it right the 1st time rather than the 3rd time!!)


<span style="font-weight: bold">IF I WERE YOU, I'd probably bleed & adjust the clutch as a 1st step. (Easy to do, little investment of parts & time...)</span>

Good Luck & let us know what you discover!!

"Cheers!"

-Bear-

 

[jlaird]

Clutch slave cylinder or MC is leaking internaly.

Start with a rebuilt or new clutch slave cylinder.

 

[Sarastro]

As Kevin indicates--when faced with a problem, we all have a tendency to assume the worst, but sometimes it's just something simple. I'd bet my spare pressure plate that it's a fairly simple hydraulic problem: fluid level, leaking cylinder, or bleeding.

 

[kcbugeye1275]

If it has a flexible hose to the slave, it could be collapsed.

 

[bugimike]

Since this is a new purchase, I would start with checking if there is enough oil in the tranny since the problem started after the car was run for a while and warmed up. If the oil is topped up in the tranny, then I would look at the hydraulics! To check tranny oil, remove the tunnel plug at about drivers knee, remove the fill-plug (11/16th socket and about a 6" extension...and a universal joint helps too!) and take a look. Tranny should be filled with engine oil to the point of just coming out of the plug-hole!

 

[WALTER]

How do you adjust the clutch? Seems to me there is enough hydraulic pressure or there isn't.

Walter

 

[Sarastro]

Bugeye clutches aren't adjustable, but I've found that sometimes the pressure plate isn't set up right, so switching to a different length slave-cylinder pushrod can be helpful.

But before worrying about esoteric things like that, do all the suggested checks.

By the way, it's not so unusual to find 80-weight gear oil in bugeye transmissions, instead of the correct 30 weight or 20W30. I don't know what that would do, but it can't be good. So, changing the oil isn't a bad idea.

 

[BugEyeBear]

Common adjustment on most all hydraulic clutch systems is done either at the master cylinder end or at the slave end of the system.

Basically you want to be certain that the clutch hydraulics are not putting pressure on the clutch fork when the pedal is released (UP). This is accomplished by ensuring that a slight amount of slack exists when the hydraulics are disengaged (i.e. when the clutch is ENGAGED; pedal is UP).

Early type of Sprite clutch has a dual unit master cylinder (serving both the clutch and the brake). When you replace this unit it is essential that you adjust the two push-rods that operate the mechanism. Their length must be set so that there is at least 0.8mm of free play before they start to operate. This ensures that the hydraulics are not putting pressure on the clutch mechanism when the hydraulics are disengaged (i.e. when the clutch is ENGAGED; pedal is UP). Without this free play you can have a condition where the hydraulics are constantly engaged and are thus causing the clutch to be slightly disengaged even when the clutch pedal is up! This will result in clutch slip (will be worse as the clutch disc wears).

Next thing to check is that you are getting constant travel of the clutch slave rod as the clutch pedal is depressed. Have a helper slowly depress the pedal while you observe the movement of the slave rod. Have the helper call out, "Start", "Half", "Stop" to note relative position of the pedal. You should see constant movement of the slave rod to match the movement of the pedal.

Finally observe the movement of the clutch fork arm. Its movement should also be smooth, without any irregular or "uncontrolled" motion.


It is probably worth noting that the clutch slave rod is a different size for the different engine sizes. 948cc & 1098cc use a 2 3/8" rod; 1275cc uses a 2 11/16" rod; and 1500cc uses a 3 1/16" rod. OBVIOUSLY using the wrong size rod will either cause clutch slipping or lack of disengagement. (Although I have seen cases where people have used a "customized" rod length to match the needs of their particular combination of parts (engine, trans, flywheel, clutch, etc.))


More modern clutch mechanisms typically move the hydraulic adjustment to the slave end. Again, you want to ensure that a slight amount of free play exists before the slave rod engages the clutch arm. (This is typically accomplished via a threaded slave rod & a fork contact "ball" that is positioned on this rod with a lock nut of some kind.)


IN SHORT, you want to be certain that the clutch hydraulics are fully disengaged when the pedal is up, AND you want to be certain that you are getting full travel of the clutch system when the pedal is down. IF your partucular installation deviates from stock you might need to accomodate this via a custom (or adjustable) length slave rod.

"Cheers!"

-Bear-

 

[BugEyeBear]

...it's not so unusual to find 80-weight gear oil in bugeye transmissions, instead of the correct 30 weight or 20W30. I don't know what that would do, but it can't be good. So, changing the oil isn't a bad idea.

Typically too thick of an oil will cause shifting to be difficult when the trans is cold.

I had a mini pick-up that "Jiffy Lube" had put 90W oil in the trans ("thanks for nuthin'!"). On cold mornings I had to force it to shift, and it tended to grind until it warmed up.
I drained the "syrup" out of it, replaced it w 30W and it was shifting like new again!

"Cheers!"

-Bear-

 

[bugimike]

Since the problem seemed to occur after the car was run for a while, which is the opposite of what would happen with too heavy a weight of oil, I would tend to think that either the tranny is low on oil or the problem lies in the clutch hydraulics. You could have a drop in hydraulic pressure due to leakage in the rubber cups in the master cylinder or slave cylinder that occurs after some usage! If you try "pumping" the clutch pedal when the problem occurs and this helps shifting, then that is where I would look!