Moss Motors, Ltd

for those who have been following my progress, you know that i have ran into problems with my ignition, brakes (front and rear), bad fuel flow, and carb. adjustments.  All of that has been conquered with the help of all of you on this forum.  I now have moved on to my clutch so that i may accually be able to road test my MGB.  I have run into a stump, i have found similar threads is this, but none were apperently helpful enough in my situation.

I have rebuilt my master cylinder. I have rebuilt my slave cylinder.  I have checked for leaks in the hydraulic line and flex hose from the master to the slave...none found.  the flex hose is fairly new and has NOT been twisted to damage it.  I believe that I have bled the system (clutch) well thanks to the help of reading others threads on this forum.  I had to use various trick to get it done, but I feel that it is bled thoroughly. 

My B is up in the air on 4 jack stands.  When I start the engine, I can shift into 1st, 2nd, 3rd, and 4th gears without even using the cluth pedal.  But, I cannot seem to get it to go into reverse with or without the use of the clutch.

When I first turned on the engine (in neutral), bith of the rear wheels were turning.  To adjust this, I tightened down on the drum brakes just until they stopped turning.

when the clutch pedal is pressed down, the slave cylinder pushes on the arm for the release bearing about 1/2 - 3/4 inch out, but then it takes about 5 seconds to build up pressure again before i can press in on the clutch again. Without waiting those 5 secs. the pedal will be pressed easily without feeling any resistance or pressure.

I am not sure wether I have a bleeding problem, a clutch problem, or a gearbox problem...or any combination of those.  I was going to try to get into the cluch from under the car by removing the gearbox, but I have a feeling that my problem goes beyond that and I am going to have to pull the whole engine out.  I know that pulling the engine is the recomended way to get to the clutch as well.  Again, this is something I have never done before, but if it is neccessary, I will learn from experience and with the help of those on this forum.

thank you in advance for all those who respond.

joel

fire,

You may have a clutch mechanical problem, but I'm not convinced of it. Your fifth paragraph reveals that you may still have a hydraulic problem. It will always be easier to get into the synchromeshed gears (1st thru 4th) than into reverse. Often, even when everything is just fine, reverse doesn't seem to want to cooperate. It is wise practice to engage first gear, and while holding the clutch down quickly slip into reverse. I have an even more eloborate habit of going into second gear, rocking forward into first, and THEN selecting reverse. This is probably just left over from my beloved MGA driving wherein there is no synchromesh in first gear either. In any event, first selecting a low synchromeshed gear brings things to a stop in the gearbox and allows the straight cut gears to engage. However, sometimes they stop tooth to tooth and still are reluctant. If this happens all one needs to do is neutralize, let the clutch up, and repeat the process. It can all be done in two winks. Certainly it takes a lot longer to explain it! Try pumping the heck out of the clutch pedal while in neutral with the engine running and then slipping it into reverse. If it goes in this way you almost certainly have a hydraulic problem, whether it's air or internal leakage.

In your case though, the fact that it "takes about 5 seconds to build up pressure again" reveals that there is something going wrong in the release system. I'd be willing to bet that if it's a hydraulic problem, it's in the master cylinder. I've been hearing a lot of this lately, and it makes me wonder if the kits are not what they used to be or perhaps some folks are not being critical enough concerning the rebuildability of their old cylinder. The bore must be completely free of scarring or pits, and must be refinished and polished in odrer to accept the new seals without damaging them and to seal well enough to function reliably. You must be very careful to get the rubber pieces back into place without damaging them (sometimes quite a trick) and all in the right order.

You describe forward movement of about 1/2 to 3/4 of an inch at the pushrod. This is a little shy of what is good. Let's take another good look at that master cylinder, and at the same time at all the mechanical bits you can access from the outside of the bell housing, such as the clevis pins and clevises, before we resign ourselves to pulling the engine and transmission. By the way, it is actually possible to pull the transmission off the back of the engine without removing the engine or cutting anything.However, I don't reccomend it at all. It's a bear of an uncomfortable job, and it risks hurting the clutch on the way back in. I repeat, it is no fun, and there is precious little time saved. Pull both as a unit and put them on the floor where you can give them proper careful service and cleaning. This also allows you to check up on motor mounts, the starter, and the rear plate and seal. A thorough job is more satisfying and gives greater peace of mind. There is really no reason to hurry if you are doing the work for yourself. Shops like mine have to worry about the time we put into things and meeting deadlines, and this is a shortcut even we don't take. Unfortunately, we often don't rebuild master or slave cylinders anymore for the simple reason that the labor to take the time to do the job well exceeds the price of a new unit. I don't like it, but that's the modern reality of business. And, we are trying to be a good steward of our clients' dollars.

Let me know how its going.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

mororbill,

thanks for your info, haven't heard from you in awhile. I will take out the master cylinder again and check the seals and the bore.  I have already taken the slave apart twice within the last 2 days.  I'm sure that this is in good condition.  I will get back to you again after I have bled the line again.

Also wanted to mention that when the car was in 3rd and 4th gear, the shifter was shaking...I mean that I could basiclly feel the gears turning though the shifter...Is this normal?

I was also curious about the way my rear wheels were turning in the neutral position. Did I correct that ok, or is that telling you of another problem that I will need to address?

thanks again for your help.

joel

motorbill,

I took the master apart...nothing seemed to be out of order with it.  The seals looked good, it wasn't put together wrong, the bore seemed to be smooth.  I cleaned it up, honed out the bore and put it all back together.  I put some teflon tape on the threads of the fitting that fits into the banjo fitting just to be sure there wasn't a small leak that I could not detect.  refilled the master cylinder and rebled the line...the clutch pedal is definatly, without a doubt in my mind working properly.  The pedal accually wants to push my foot up as I push down on it, the slave is pushing the rod about 3/4-1 inch, I do not have to wait 5 seconds, I can just keep pumping it. 

after bleeding the master, I tried to put the gear shifter into reverse from 1st gear, It worked.  I played around with it some more and found that I can now get it into reverse from neutral now too.  the only concern is that when it goes into reverse, it grinds on the way.  I have to slap it into reverse (shift it really fast) and it still grinds.  Is this something that I still may be able to fix?  the car is still up on stands, I am going to put the tires back on tomorow and lower the car down and try backing it out of my garage.  Earlier this year, I was able to shift into all gears while up off the ground, but once I dropped it to the ground, I could not shift at all unless the engine was off...This is when I relized that I had no brakes...that was a funny day...watching me turn the car around in my driveway with no brakes and having to start the car in gear...anyways, I'll try it again tomorow and see how it goes.  of course I will post here with the results.

 thanks afgain for all your help, motorbill...you always seem to come through for me.

joel

You'll get a crunch because the gears are unsynchronised and you are moving the actual gear, a straight cut idler gear, directly - no dog clutches & constant mesh here. There's nothing wrong.

If you don't wait after pressing the clutch, all the gears are still turning inside the 'box and come together in movement when you shift, result - crrrrunch! This is common on many cars old and new. My '67 B has no synchro on 1st either, so will crunch if you are too fast with the lever at the lights. The best thing to do is as motorbill described... select another gear before attempting to find reverse, this uses that gear's synchro to "apply the brakes" to the transmission, so that the gears are stationary when you shift into reverse. If you can't get reverse (happens because the teeth on the idler gear are lined up wrongly) just pop the clutch up and try the whole thing again. It's an easy discipline - I have to do this every time I shift into first - and find myself doing it on all cars I drive...

 Cheers,

Ed

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I want my MGB

ed,

What I don't understand is that if I put the gears in 1st then straight into reverse from 1st, then the gears are already moving in the forward direction then slamming them into the opposite.  Maybe I don't understand how the system works that well, but to me it seems that by doing that it would mess things up even more.  And besides, the gears grind going into reverse whether I go staight from neutral or if I go from 1st gear.  How does puting it in 1st gear apply "the brakes"?  Should I press on the clutch and the brake at the same time when I put it into reverse?

joel

OK assuming the car is stationary: the prop shaft & gearbox output shaft are not moving, with engine running, car in neutral the input gear and laygear are rotating. Push down the clutch, the gears continue rotating under their own momentum until friction stops them

If you shift into a synchronised gear, the synchro hub "brakes" the input and output dog clutches to match the speed of the gears before they engage - both will then be stationary if the car is not moving.

What can happen is a minor amount of drive to the gearbox even with the clutch pressed (tiny bit of drag via the pilot bushing etc. etc.) this could cause gears to start moving whilst you go from 1st into reverse.

I hope that is perhaps a bit clearer.

 Cheers,

Ed

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I want my MGB

ed,

I think I'll have to take your explanation and refer to the books to make sense of it all...I do appretiate your trying to clerify how it all works.

thanks,

joel

Joel,

Confused by the gearbox diagram in the Moss catalogue, I searched and found this website a few years ago. It gives an excellent description of how a typical transmission works, from the basics of gear ratios to the added refinements like selector mechanisms, constant mesh gears and synchromesh.

http://auto.howstuffworks.com/transmission.htm

Perhaps you will find it of interest.

Cheers,

Ed

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I want my MGB

thanks ed, I'll be sure to check that out.

joel

Do check out the How Stuff Works website. Ed gave a very good explanation of what goes on, but there's nothing like seeing the components and theie relative position and movement to begin to understand the elements at work. I have given seminars in the past on transmissions and it's amazing to watch the "lights go on" as people begin to see just what all that crunching is about, and why we call it "synchromesh" and on and on. I wish I could do one of these demonstrations here on the forum, but I'm afraid the particular medium inhibits that, at least for a computer neanderthal.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Hi Bill

Just to add to what you say - it's also really worth checking out John Twist's (of University Motors fame) YouTube videos. He is very skilful at explaining problems, diagnosis and repairs. There are a couple of gearbox videos, one with a cutaway box, that really helps to show how things operate. http://www.youtube.com/user/Universitymotorsltd

Ed

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I want my MGB

motorbill and ed,

I am definatly going to check out those sites within the next week.  I again thank you for all of your help.

Today I put the tires back on and dropped the car down off the jack stands.  I wanted the move the car out of the garage so that I could for 1 be sure that i could accually get it in gear and able to drive it and 2 to rearange my gargae for the winter months which are right around the corner.

Now that the car is sitting on all 4 tires, I cannot get the car into ANY gear.  The clutch still seems to be bled well and the slave is still moving back and forth by at least 3/4 - 1 inch.  When I hold in the clutch pedal and atempt to put it in 1st gear, the car accually rolls forward, but it will not go into gear.  Reverse just grinds and will not go into gear at all.  what could be my problem now? 

joel

Hmm. It sounds as if, for some reason, your clutch still is not disengaging properly.

There's an outside chance the plates & disk are stuck together, or there is still insufficient movement of the slave cylinder.

Just one question for you - Has the clutch worked at all recently, or has it always been an unknown quantity?

Ed

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I want my MGB

ed,

this car has sat in my garage for 5 years and before that, it sat at it's previous location for a couple years there as well''  It has sat, undriven, for at least 6+ years.

joel