Lotus Elan and Lotus Elan Plus 2 Forums

Well I had to have the Europa brought home on a flat bed yesterday,(Footman James insurance works) I know this is an Elan Forum but it has the same servo as my Sprint (mk2B) and some +2's
NOTE. U.K. spec brakes single master cylinder and servo.
Problem all four brakes locked on, I could unlock the brakes by loosening a brake pipe but first push on the brake pedal brakes lock up again, disconnected vacuum line did not help.The master cylinder has "free play" in the rod so it is not building up pressure and the brakes are cold.
Servo air filter clean.
Master cyl. cap vented.
I overhauled both the Europa and Sprint servo's about 2 years ago and that included resleeving the cylinders although I did not replace the large diaphram as they were in good condition.
I do remember this happened when I first put the Europa servo on but rebleeding freed it off, it has been fine since but it has not had a great deal of use.
I have now bridged the pipes and removed the servo and no more lock up, please dont suggest I leave the servo off as this does not solve the problem and I like the feel of a servo.
I do not want to start fitting different bore master cyl, +2 calipers etc,etc
Any suggestions ? as to a likely cause?
Brian

Just a quickie,sounds like the valve is sticking in the open position?
John

Hi There - If you look at the home page you will see some titles on the left hand side of the page - one is entitled Brakes. Under that section I found this which may be of some help.

Lotus Service Bulletin - Brakes Locking On

Lotus Service Bulletin

Class 111
Number 1970/045
Type All Models
Date 16.10.1970

Title: Brakes 'Locking On'
Reason: Cases have occurred where brakes have 'mysteriously' locked on. In the instances we have been able to investigate with Girling Ltd., this has been proved to be caused by the servo unit 'pushing back' (see Girling publications G.149/2 and G.283H).
Charges: U . K. - Warranty???????
EXPORT - Factory?????
??????????????? - Distributor NO
NO
NO
Action: In most cases when this happens, the brakes can be freed by 'kicking' the brake pedal sharply down. The servo unit should be checked in accordance with the information published in Section 'J' (Braking System) of the Workshop Manuals and with the Girling publications listed above.

Good luck
Top of Page

That is why I took the servo off my baby Elan.

<!--QuoteBegin-types26/36/74+May 25 2005, 11:08 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (types26/36/74 @ May 25 2005, 11:08 AM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->please dont suggest I leave the servo off as this does not solve the problem
[/quote]

Brian

Problem all four brakes locked on

I have now bridged the pipes and removed the servo and no more lock up

Perhaps the problem needs to be restated?

<!--QuoteBegin-mrjxc09+May 25 2005, 03:07 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (mrjxc09 @ May 25 2005, 03:07 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->sounds like the valve is sticking in the open position?
[/quote]

John,
Are you refering to the air valve? if so I think it unlikely as it happens with no vacuum connected, on the mk2b there are two valves on a rocking lever, I removed the cover and pulled the valves off their seats but this made no difference and did not release the fluid pressure.
Brian

<!--QuoteBegin-carrierdave+May 25 2005, 04:17 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (carrierdave @ May 25 2005, 04:17 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->

Lotus Service Bulletin - Brakes Locking On

Lotus Service Bulletin

Class 111
Number 1970/045
Type All Models
Date 16.10.1970

Title: Brakes 'Locking On'
Reason: Cases have occurred where brakes have 'mysteriously' locked on. In the instances we have been able to investigate with Girling Ltd., this has been proved to be caused by the servo unit 'pushing back' (see Girling publications G.149/2 and G.283H).

Action: In most cases when this happens, the brakes can be freed by 'kicking' the brake pedal sharply down. The servo unit should be checked in accordance with the information published in Section 'J' (Braking System) of the Workshop Manuals and with the Girling publications listed above.

[/quote]

Dave,
Thanks for that, as the bulletin is dated 1970 I'm not sure it covers the mk2b as I thought the mk2b was on the later cars and I think it may refer to the earlier servo.
I know there is a mod about fitting a spring under the air valve but think this is for the earlier type, there was no way my brakes would release by kicking the pedal as I tried it.
The workshop manual only gives basic tests and does not cover servo overhaul, to quote: "fit new servo"
I do have a servo rebuild sheet but I dont think its specific to a mk2b, does anyone have the Girling publications refered to? I have a fax number if needed.
Brian

Bit confused about the problem, but brakes sticking on can be a sign of a flexible hose collapsing internally. They can look OK on the outside.
Mine were, but it was easy to tell, they had the consistancy of tar!
Cheers
tim

<!--QuoteBegin-tdafforn+May 26 2005, 07:53 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tdafforn @ May 26 2005, 07:53 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->Bit confused about the problem,[/quote]

The problem is that the servo is holding fluid pressure and not releasing, it happens whether the servo is connected to vacuum or not.
The hoses are all fine as the system releases the brakes if the servo is removed from the system.
The problem is definitely with the servo and dispite a web search there appears to be no information available on Mk2b servo's.
Brian

Brian,

Brian,
Forgot the tesxt!!!!!!

However, IIRC there is a chap who advertises in club lotus mags who overhauls brakes servos etc, perhaps he is worth a call. Some where near Manchester as I recall. Don't have a magazine and his phone number to hand at the moment, but I will dig one out for you tomorrow if you dont have one.

cheers
Mark

ps from recent posts i recall this as an o-ring problrm on a valve (but my memeory is not great). Solution, remove one of them, I think.

Paul Norton at <a href='http://www.norton-servos.co.uk/' target='_blank'>Norton Classic Servos</a> is the guy you need on +44 1494 563254.

Highly recommended.

Hi

I remember this happening to me in my plus 2. Right at a busy set of traffic lights in Beckenham on a Friday afternoon. People thought that I was being bloody minded by not pushing it out of the way. Hard to do with all 4 wheels locked solid. I cleaned the air filter on the servo and tapped it a few times with a spanner and never had the problem again. I did keep a bleed nipple spanner in the glovebox afterwards though.

Someone told me that the servo should be mounted with the filter facing downwards.

Please let me know how you get on. I have a plus 2 servo that needs rebuilding and so does a friend of mine.

Berni

Hi Brian,
The MK2b was fitted on the early cars, mine is a 1969 built +2s and it has its original MK2b servo. Therefore the 1970 sheet is correct for your car. As for a rebuild sheet - If you call Club Lotus they have a sheet for both types MK2 and MK2b (I have a copy I can fax to you) courtesy of Gordon Lund.

The rebuild instructions look reasonably easy to follow - If you decide to do it let us know how it went.

As Berni commented, I have also herd that the air connection to the servo should point downwards, mine does although it has not been on the road long enough to come accross the problem.

Good luck

David
B)