Servo sticking

[Gasman]

Dear all

I think my previously 'serviced ' girling brake servo is not releasing on occasions.
Prices for service kits..... wow. Prices for new lockhead replacements approx ?250+!!
Question- are the replacement servos sold for MGs etc (from ?88), which are a third of the price and look the same, OK as replacements?
What's the difference? is it only in degree of brake assist? or matched to the vacuum available, I'm sure the twink produces more vacuum than a MG unit.

Comments gratefully received


Mark

[garyeanderson]

Hi Mark

There is a search function at the top of the page. I submitted servo sticking and recieved 26 responces. this has been covered a few times. maybe the answer to your question is there, if not it may help narrow down your question to something that will get the responce you are looking for.
Gary

[john.p.clegg]

Mark
The intermittent sticking servo can be cured quite easily by the fitment of a light spring in the air valve,a ten minute job...

John

[Gasman]

Thanks guys

The light spring sounds worth a go, but I'm not sure where exactly you mean.

Also my real question was, are all the lockheed servos the same? The price seems to vary threefold between MG and LLotus suppliers for what I thought must be a straightforward replacement.

Cheers

Mark

[Robbie693]

All Lockheed servos are not the same. When I bought mine there was a choice of two, one with a 8" shell diameter and the other 7". I since found out that the 8" at least comes with two bore sizes also. The lockheed part number for the Plus 2 servo is LR 18221.

?250 is very expensive, I got mine for ?120.00 from this guy:

http://www.classicpartstrader.co.uk/overview.htm


The Plus 2 servo is not listed on his site, but he does have them. I found out through his Ebay shop. Give him a call, his name is Ian.

[types26/36]

The intermittent sticking servo can be cured quite easily by the fitment of a light spring in the air valve,

John, is this applicable to a Girling Servo? I thought the spring under the air valve was a mod for a Lockheed unit, I can't see how you would do it on a Girling (well a mk2b anyway) the air valve on the MK2b works on a rocking lever arrangment which already has a small sprng on it.

[gordonlund]

Mark, You say your servo is a Girling but refer to Lockheed replacements.

Girling & Lockheed units are obtainable from Classicar Automotive Cheshire but only on an exchange basis. Yes, Lockheed kits are expensive.

Which car are you referring too. The +2 uses a much bigger one than the 2 seater Elan. Original fitment was the P4 Rover for the +2 so they go back a long way. If the vacuum cylinder end plate is held in place with small nuts and bolts then that is the early type with leather vac seal. If it has a clamp band holding it together then that is the later type utilising a rubber diaphragm. This type is more expensive to repair.

Sticking servo's can be caused by a number of reasons:
1 Hydraulic oil leak into vaccum cylinder causing leather seal to swell and hence stick.
2 Ingress of dirt causing cylinder to stick.
3 Non return valve not operating properly as mentioned previously.

When they do stick on, try releasing the pressure by undoing the hydraulic pipe connection on the feed line to the brakes at the servo. If the brakes servo resets then it is probably the diaphragm sticking. If in any doubt, ring Classicar automotive. The service kits are very hard to get hold of and if you are not fully competant in servicing servo units, leave it to the specialists. Your life may depend on it!!!

Regards

Gordon

[john.p.clegg]

Mark

Yes,sorry,my fault..

John