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MG MGB Technical - My 1979 MG won't go in gear

My 1979 MG will go in gear only when the engine is off.I have a full pedal butit won't shift into any gear.
Thanks for any and all idea!!
JoJoe
S.D.L. LOHR

Is the clutch fully dis-engaging? Is the friction material all worn out? The clutch actuating system, is it working? You need to watch the clutch actuating arm from underneath, while some-one operates. Come on folks are these sound comments? Mike
J.M. Doust

Mike seems to be on the right track, but could you tell us if this problem happened suddenly or have you had difficulty changing gears over a period of time gradually getting worse.

Tony
Tony Oliver

The easiest way of finding out what the fault is is to try to select reverse. If the gear grates then the clutch is not fully disengaging. You will then need to check the throw of the fork lever which should be between 1/2" and 5/8". If this is Ok then I'm afraid the fault is internal with the clutch but if it is less than this the fault lies in the hydraulic system which should be investigated.
Iain MacKintosh

Check to see if the brake booster is hooked up to the intake... I had the vacuum line pulled to try and tune my carbs and ran across a problem very similar to that. But not sure if it would apply to you.
JRB Mr

I had this quite a few years back after fitting a new clutch. The friction plate came apart with the friction material ring spinning round the centre spline section.
c cummins

There is 1/2" throw of the fork lever. It started when I was backing out of a parking spot, didn't want to go in R, I let the clutch out and wiggled the shifter in N, then pushed the clutch backdown and it went in R, drove and shifted from 1st to 2nd back to 1st, stoped, 1st to 2nd to N (coasted to red light).
Light turned green, pushed in clutch moved shifter to all gears NOTHING! Two guys pushed me back to a parking lot off the road and I called for a tow truck.
I read what I could in The Complete Offical MGB 1975-1980, DRIVER'S HANDBOOK & WORKSHOP MANUAL, BY BENTLY PUBLISHER. Then I thought of asking for HELP.
Thanks again,
Jozettey
S.D.L. LOHR

I'm still not sure what you are saying. Does reverse gear grate when you try to select it? We must have an answer to this question before we can diagnose the problem.
Iain MacKintosh

It's beginning to sound like a selection problem inside the gearbox.

I really can't see how the servo vacuum hose would affect gear selection - engine starting and running if it had been left disconnected, yes.
PaulH Solihull

>"Light turned green, pushed in clutch moved shifter to all gears NOTHING!"

Are you saying you can select all gears but no drive? Also answer Ian's question on what happens when you try to select reverse as this will confirm if drive is going in to the box with a clutch problem. If you can select reverse without issue the problem is not in the clutch area.

From the above statement I'm starting to think gearbox, prop shaft or half shaft failure. You'll need to answer our questions for us to help narrow the field.

MGmike

M McAndrew

That would be total and permanent. From the owners description it either goes into gear when the engine is stopped but not when it is running, or comes and goes.
PaulH Solihull

Paul, agreed it would be total and permanent.
The comment about it failing at the lights and needing a tow home sounded total and permanent to me. I guess as we read different things shows just how powerful the written word can be.
My point was we need more clarity of the symptoms to help with the diagnosis as there seems to be a few inconsistencies in the posts. eg "go in gear when off" but not when running (assumed as JoJoe doesn't actually say that). Followed in the second post with "lights turned green...moved shifter to all gears nothing". One doesn't fit with the other unless the engine stopped at the lights.
I agree a clutch problem is the most likely cause of gear selection issues but not the only one and more info is required to suggest a course of action.

MGmike
PS love the website, how do you find the time...
M McAndrew

He does say on the 3rd "... didn't want to go in R, I let the clutch out and wiggled the shifter in N, then pushed the clutch backdown and it went in R, drove ...".

The first 'didn't want to go into R' could just be 'normal' baulking though, soon followed by total failure, so yes clearer statements are needed, such as to:

Does the lever go fully into every gear or is it baulking?

Does it come and go or is it now permanent?

Does it happen when the the engine is off? Running? Or both?

I'm sure there are others.

And I'm retired - from paid employment anyway :o)
PaulH Solihull

Paul,
I put that first one down to "normal" also. Lets hope we get your questions answered to move forward.

Retired.. Happy days, bring them on, can't wait... All that time to mess with the MG's :o)

MGmike
M McAndrew

Actually, it does seem as if some of the AFICIONADOS, are just waiting for a thread to come in, some are answered so fast. And thank you by the way it was not intended to be a slight, or insult. My excuse is I have the computer open all the time. In between patients, I look at the site, it keeps me sane! Mike
J.M. Doust

Sanity is overrated, that's why we own MGBs. RAY
rjm RAY

hi i have a 78 bgt that does the same thing if the engine is runing it is very hard to get any gear if not inposable. the only way to get it in gear is to pess the clutch fully put it in reverse with a little crunch from the box then put it in first. then when driving to go thro the gears as normal ie 1 2 3 4 then when slowing down 4 3 2 1 ect with no crunch but never putting it in to n, or when the engine is off it will go in to all gears very easly with the clutch fully pressd. the clutch bite is close to the floor aswell so suspect the clutch at fult
c mudie

Unless you're getting a horrible grinding noise when depressing the clutch pedal, which would indicate a faulty throwout bearing, I would concentrate my attention on the clutch hydraulics. 99% of B clutch problems are hydraulic system related. These clutches are heavy duty items that rarely see the kind of abuse that can ruin the clutches in cars with larger engines. RAY
rjm RAY

can you adjust the clutch on the hydraulics or would i have to replace the master and slave cylinder. chris
c mudie

the only "adjustment" is to bleed the clutch at the slave to ensure there is no air in the system. After that, check the slave starts to move as soon as you press the pedal (two man job!). If that's okay, it's engine out and check/renew the thrust bearing and clutch plates.

If you need help let me know, I know someone in your area who may be able to help you at good rates :o)
M McAndrew

thats gr8 i know what i will be up to this weekend lol thank you .... chris
c mudie

This thread was discussed between 02/11/2011 and 30/11/2011

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