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MG MGB Technical - Brake Servo Problem HELP!

Hello all, this is my first post and I am new to the forum. I am a first time MG owner now here is my problem.

I have just bought a 1973 MGB GT. The pipe that goes into the brake servo (I assume that deals with the vacuum) has perished and needs replacing. I have a Girling Powerstop 5204 brake servo and I cannot find where to get this part anywhere.

I have uploaded a photo, hope it works.

Thanks
Ricey

MD Rice

Moss or MG beehive or MG owners club are just some of the normal MG parts suppliers that can supply the correct vacuum hose you require.
jim soutar

It was MG Beehive that supplied me the wrong part. I described it to the guy over the phone. It's lucky the hose I received needs replacing anyway.
MD Rice

It sounds like you have a non-standard servo, therefore a non-standard pipe.
Dave O'Neill2

Standard servo would be Lockhead.

If its the vac hose a good local parts supplier can usually offer reinforced non collapsible hose that is suitable - sold by the metre (or foot !).

Do not recognize what is in your pic.

R.
richard boobier

Ok, so I have a non standard brake servo. Where can I buy a new standard servo? How much? And also how easy to fit?
MD Rice

Ricey,

It looks like you have a servo similar to that used on the MGC (and many other cars including some jags etc).

The rubber elbow is part of the connection between the valve block and vacuum chamber a good brake service workshop should be able to source them.

BUT if the servo is in poor condition you would be able to install the standard servo for less cost than repairing the Girling

Terry
T J Malloch

Where is this servo located? Your picture shows the RH side of the engine with the alternator on the right. The MGB servo in 1973 was mounted on the flat panel right at the back of the bonnet, on the opposite side to the brake and clutch reservoirs.

Terry is right, the Girling servo will be hard to get repaired. New Lockheed type servos are available for around £90 from most of the main suppliers. See on this page for example
http://www.sussexclassiccar.co.uk/shop_factory_hazel/contents/en-uk/d748.html
Mike Howlett

The servo is at the front on the left hand side if your standing looking inside the engine bay just over the wheel arch. Would I have to relocate the servo if I changed to a Lockheed? I'm having great difficulty locating this part!
MD Rice

The remote servo was originally mounted on the heater shelf on the passenger side, i.e. very near where the port on the inlet manifold for the servo vacuum hose is located. That looks like the short rubber hose between two parts of the servo as below top right. Depending on the fitment that is out of sight and you have enough room to bend a straight hose round, anything should do. I suspect that is only the equalisation port and so not subject to high vacuum like the main vacuum pipe. The standard servo has a straight bit of hose that is just pushed onto the two pipe ends, that from the back of the vacuum chamber having a metal pipe bent round to face the other one, rather than the hose having to do that job on the Powerstop

Paul Hunt

Hello Ricey, welcome,
as the servo matter is being dealt with I'll give you (mercifully cut down version of my advice to new owners)

buy and thoroughly read a copy of the Driver's Handbook (this is what would have come with the car when new) as it tells you so much you need to know to own, drive, service and maintain your car and it’s very useful to have as a paper copy (even if you get electronic copies later) – http://www.mgocshop.co.uk/catalog/Online_Catalogue_Handbooks_5.html

also very useful, you can get suppliers catalogues for free to get you started to see where things go but in my personal opinion they’re not as good as a paper copy like – http://www.mgocshop.co.uk/catalog/Online_Catalogue_Parts_Lists_3.html

you can also get an excellent DVD that includes original Parts Catalogues, Parts Fiches, Workshop Manuals and owners Handbooks to have in electronic format –
http://www.rimmerbros.co.uk/Item--i-GRID012000

John Twist gives great, clear advice on serving and repairs in his 200+ videos – http://www.youtube.com/user/Universitymotorsltd#g/u

a truly excellent site crammed with information for MGBs is (contributor here) Paul Hunt’s –
http://www.mgb-stuff.org.uk/hometext.htm

there so much a newbie can pick up with classics (I've got 20sets of non-mechanical, non-technical general note) but as you've already found it I'll just add this -
• don’t assume the part or component fitted to your car is the original or correct type or that it is fitted or working correctly, check and cross reference the information you have – and do the same when ordering parts or components, check and cross reference the information

• always check and try to do the work when the shops are open so that you can get things that are unexpectedly needed

• new parts or components can be faulty so don’t assume because it’s new it must work – if possible check that all new parts and components work fully and will fit your car well in advance of starting the work so that you can exchange for the relevant item any that don’t work or wont fit before you start the work
Nigel Atkins

Thanks Nigel and everyone else. This is all a bit new to me. I'm 27 and this is my first project. I have a general understanding on cars engine wise. I used to own and run a bodyshop with a few friends a couple of years back so body work is no problem for me.

I am really struggling to find this part and looking at the servo it is looking a bit worse for wear. What would I need to replace it and also am I going to need to relocate it and buy new brackets for it?

If required I can post more pictures.
MD Rice

OK here is a picture I pinched off an advert showing the usual under bonnet arrangement for your car. You will note the Lockheed servo in the top right corner of the photo. It is black with a white disc on it. You can see the hydraulic pipes going across the bulkhead from the master cylinder and back to the 4-way junction and the vacuum hose coming off the inlet manifold.

One thing you may want to consider is to do without a servo at all. Up to about 1971 MGBs had no servo. When the remote servo was fitted as standard the brakes weren't altered in any way, so removing the servo and just connecting the hydraulic pipe from the master cylinder directly to the 4-way junction gives you the same brakes as the cars had from 1962 to 1971. They need a marginally heavier push, but work just as well, and you've lost the complication of the servo altogether. Worth a thought. You will have to plug the vacuum take-off point.


Mike Howlett

Ricey,
Mike has voiced the thought I had, try going without the servo, it's more likely old little use hard tyres (regardless of tread left) and possibly old hard pads with inhibit the cars stopping more than a little more leg power from you

despite the new looking oil filter and HT leads it looks like either the car might have been in a damp location or the car not used much at some stage

if it's lack of use then many small or large recommissioning initial running wrinkles could need sorting

I always advise newbies to buy the Driver's Handbook and run through the 36k-mile service or checks detailed in there, staggered between running the car frequently, the more the car is driven the quicker it'll get better and the quicker you'll learn to drive it the way it should be driven

email me if you want my general non-mechanical, non-technical notes nigel atkins (one word) at bt internet (one word) dot com
Nigel Atkins

Thanks Mike and Nigel. The car has spent the last 4 years in a museum whilst the owner was in Germany (posted there military man like myself). It has only done 28000 miles in its entire 40 year existence.

Is taking the servo out completely something I could do easily or best left to a professional?
MD Rice

To remove the servo you will need to disconnect and remove the hydraulic pipes that go from the master cylinder to the servo and from the servo to the 4-way union. You then disconnect the large vacuum hose at the engine end and plug the opening on the inlet manifold. Then you can unbolt the servo and bin it.

Now you have to obtain a new piece of hydraulic pipe to go from the master cylinder directly to the 4-way union. Any garage could make this up for you - just tell them the length you need and show them the imperial screw fittings on the ends - otherwise they will put metric ones on. They could cut the fittings off the old pipes and re-use them. It's possible you could use one of the pipes you have removed without buying a new piece, but they may be a bit long.

Once the new pipe is fitted the brakes have to be bled to get rid of all the air bubbles. Brakes are your lifeline, so if you aren't confident about doing this, find someone who is competent to do it for you.

Believe me, the brakes are fine without a servo. I have driven tens of thousands of miles in an unservoed 1971 MGB without any cause for concern. BUT, the rest of the system needs to be in good order - good discs, good drums, good pads and shoes, good calipers (not with stuck pistons), good rear slave cylinders (not leaking), and good flexible hoses. All these can deteriorate with time and non-use.
Mike Howlett

I have managed to source the part and the guys were very helpful at PowerTrack LTD.

http://www.powertrackbrakes.co.uk/

Thought they deserved a mention.
MD Rice

The £90 Servo is the Chinese lookalike viz. Reverse engineered.
The original Lockheed is available from Delphi-Lockheed Dealers but is twice+ the price and can be identified by LOCKHEED cast in the valve body.
A Kit comes with a bracket,pipe and NRV.
Geoff F..
Geoff Farthing

Of course you can remove the Hose from the manifold and blank it off, remove the servo and get a double ended female connector and join the brake pipes together, bleed system job done. (may have to adjust fuel mixture)

I use my BGT without a servo, yes the pedal is a bit heavy but no problem really.

Ken Harris

The single-circuit remote servo was only an option anyway, so the brakes are fine without it. I didn't notice it on a pals car that doesn't have a servo and I didn't know, on another car where it had been disabled and I was looking for any difference it was barely noticeable. Removing it does get rid of the potentially serious issue where seal failure swallows all your brake fluid, leaving you with no brakes.
Paul Hunt

years ago I done a very unscientific test - I had a BGT with a servo and a mate a roadster without

I dove my car and braked hard at a certain point, we swapped cars and I then drove his car along the same bit of road at the same speed and braked hard at the same point, it stopped in more or less the same distance

being used to the feel of the servo'd pedal in my car the non-servo'd pedal felt very slightly harder under foot but that would have been forgotten after the first journey driving it, my mate said the same
Nigel Atkins

Servos do nothing for braking performance, they simply reduce the effort required at the pedal.

MGB servos are vary low ratio - especially the remote ones - and can't be compared with modern high ratio servos.

Chris at Octarine Services

This thread was discussed between 05/06/2013 and 21/06/2013

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