Lotus Elan

Brake Probs after refurbishment

PostPost by: Barney » Fri Oct 24, 2008 5:42 pm

Last Year the brake system was overhauled with new calipers and pads being fitted after a long time off road.

On the first drive home from the garage the brakes began to momentarily stick on, just a fraction longer than necessary. Braking wasn't "spectacular". I talked it over with the proprietor of the garage who thought this might be a sticky Master Cylinder and may resolve itself whilst the pads (Green Stuff) and new disks needed to bed in.

I only had the opportunity to do a couple of short runs near my house before I had to go back to work. In this time the problem of the sticky brakes was replaced by a very hard peddle and very poor brake effect. --- Very nearly caused an "Oh Sh*t!" moment as I narrowly avoided hitting my other car (acting as back-up during the trials) in a double whammy.

The car is fitted with a remote servo in the nose and the vacuum is taken from No. 4 manifold through ⅜" or ?" ID rubber hoses with a non-return valve situated on the engine bulkhead. These hoses are 20 years old at least and may be just past it?

I'm not particularly happy with the appearance of this routing/solution but I am happy to continue with it, if it will work.

I wonder however, if I could take the vacuum from the headlight system, i.e. the crossmember reservoir?
Is this unsafe or an error in principle? This would remove the need for the long run of hose from the rear and opposite side of the engine bay. :?:

Hopefully somebody will be able to point me towards the culprit or the right direction to systematically check the system to identify/isolate the fault and at the same time guide me in the wisdom (or not) of my suggestion. I am accutely aware that Colin Chapman used a separate vacuum source in plus 2's and wonder why.

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Barney
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PostPost by: elansprint71 » Fri Oct 24, 2008 7:02 pm

Have you replaced the flexible hoses? My guess is that they have ballooned internally- common problem if they are old and usually there is no sign from the outside.
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PostPost by: alexblack13 » Fri Oct 24, 2008 9:29 pm

Hi All, Barney,
I took the short route with the piping for the vac' system. Single pipe from manifold via non return valve (CHECK IT) to the 't' pc on the vac' res'/crossmember. On the other side of the 't' I fitted another 't' pc. One end went to the headlamp sw' the other went to the servo. The way I see it is that the vac 'pressure' if you like, equalizes in the system. Whatever you use (Brake or h/lamps) will produce a reduction in the whole system which in turn is 'topped up' from the manifold vac' presure at any given time. I used hard plastic / nylon, 3/8 '' dia piping, with new rubber con's. So far so ....

I take it you overhauled all the brake system? No stuck pistons etc? All the calipers working as they should be?

Keep us posted..

Alex B.... 8)
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PostPost by: Barney » Fri Oct 24, 2008 11:28 pm

Pete/Alex

Thanks for your input.

I take it you overhauled all the brake system? No stuck pistons etc? All the calipers working as they should be?


Yes, the calipers were completely overhauled - or so says the invoice - but the servo (booster), N/R valve and Master Cylinder not so. Internals of the calipers were a grey mushy porridge, as were the internal chambers of the Webers.

Getting the car running (to MOT standard) was done by a Lotus garage on a minimal budget (in between other projects whilst I was at sea).
The car had been in storage for too many years and was too much for me to complete within my leave periods with my limited technical prowess. (It takes me three times longer to do technical jobs - I have a habit of breaking things - 2 steps forward and 3 back)

Problems were compounded when at my last house the car was flooded once to door sill level.

Will start with the hoses and work from there. One small section of the existing vacuum hose is a piece of acetylene hose, so probably due renewal!

More (I'm sure) to follow. . . . .

:shock: :shock: By the way, jumping threads a little my UK 13H (US 14EEEE) feet have problems too. Anybody know of a retired Geisha girl foot binder? :shock: :shock:

Cheers
Barney
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PostPost by: Vanden Perre » Sat Oct 25, 2008 10:57 am

Barney,

If I was you I would by pass the servo. My S3 from May 66 had obviously a servo as shown by the pipe coming out of the master cylinder going to the nose of the car, making a loop and from there going to the callipers. There is also a connection in the loop which tends to show that the servo was removed by the previous owner. Brakes are all right without the servo.
Therefore in your case why not by pass the servo and check if the braking improves? If I am right the pads for non servo brakes are not the same for servo ones and it will not be perfect but al least you would know if it is the servo and if yes decide if you really need it.
Just an idea but in any case double check with someone else as I am no brake specialist and wouldn't like you breaking your neck (or even worse your Elan :D) following my advice.

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PostPost by: rgh0 » Sun Oct 26, 2008 2:38 am

I would bet your servo has problems. Make sure the vacuum supply is working OK and if so and you still have sticking and poor response then I suspect a servo overhaul is needed.

Bypassing the servo completely should demonstrate if the sticking problem is in the servo ( most likely) or in any of the other components (unlikely IMHO).

If you just disconnect the vacuum line to the servo and the sticking goes away then it is in the vacuum boost circuit of the servo not in the servo brake fluid cylinder components.

cheers
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PostPost by: Elanintheforest » Sun Oct 26, 2008 7:53 am

Barney
Is the servo a Lockheed or the original type Girling? Lockheed servos are used as replacements for the Girling, and do have a problem with a valve, whereby the brakes stick on. A recent acquisition of mine, a S4, has this same problem, and when it sticks, the brakes seem to be about 50% of what I'm used to.

There is a replacement valve, available from Classicar Automotive, which I must get around to fixing up as well. The alternative, as mentioned above, is to bypass the servo altogether, but make sure you have soft pads fitted. I don't think that the S2 had a servo as standard, except for that elusive S/E version

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PostPost by: miked » Sun Oct 26, 2008 7:15 pm

I agree with Rohan, in my case it was the metal valve in the brake fluid.
I chased this same fault down earlier this year. Mine has a Lockheed universal fitted after my original failed two years after overhaul.

I too went through the lot. All new rubbers (calipers and M Cyl'), already had braided hoses. It was the metal valve in the servo'. Not the nlyon top bit. The brakes go to about 50% and they hang on for an instant. Very annoying!

I talked to Classicar Automotive (who are great guys) and stripped the top of the servo cleaned and greased the little piston. A small amount of rust binds it. Very subtle fault when you open up. There is a spring that should be fiited that Lockeed no longer fit. Dave had a spare so I got this. I do not know whether he has anymore. They do shoot themsleves in the foot with business doing this. I have been going for a long time and am regular spender! I can't say enough good things about these guys. Top work, good advice and good prices.

Took the car out and it is back to the "dogs B*llocks".

The cost of non Lotus dealer Lockeed servos was only about ?130 if you shop around. It is less cost to buy a new one that have total refurb' if more than this.

I posted on here a while ago about this problem and what I was told to sovle it. It is due to wet/damp air going into the servo in the nose. Lockheed had a small cap (a mod) for the servo air filter to allow a pipe to remotely pick up clean dry air in the engine bay. I chased for weeks and failed to find it anywhere. I did try everywhere. Even posted on "wanted" in here. I solved it with an spray can top plastic lid and piece of tube. The servo breathes to near my windscren washer bag in dryer air than the nose.


Mike



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PostPost by: penelan » Mon Apr 12, 2010 9:40 am

Elanintheforest wrote:Barney
Is the servo a Lockheed or the original type Girling? Lockheed servos are used as replacements for the Girling, and do have a problem with a valve, whereby the brakes stick on. A recent acquisition of mine, a S4, has this same problem, and when it sticks, the brakes seem to be about 50% of what I'm used to.

There is a replacement valve, available from Classicar Automotive, which I must get around to fixing up as well. The alternative, as mentioned above, is to bypass the servo altogether, but make sure you have soft pads fitted. I don't think that the S2 had a servo as standard, except for that elusive S/E version

Mark


Hi Mark -We have a '71 S4 Sprint which has some issues with brakes ( it's been converted to dual circuit with Lockhead servos ) and engine tune ( hesitant / stalling ). We are in Ross-On- Wye. In this area are there any good specialists who understand the Elan and it's foibles. Maybe you no longer have your S4 in which case sorry to trouble you!

Cheers

Chas
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PostPost by: Galwaylotus » Mon Apr 12, 2010 7:41 pm

Must be the servo. If the car was flooded to the sills and sat for a few years, I'd be surprised if the servo wasn't affected. When mine siezed, I took it off and replaced the master cylinder with a tandem m/c for safety. Changed to Greenstuff front pads and I'm happy even though it took a little getting used to the non-assisted brakes. They stop fine - just a little bit different feel. I wouldn't go back!!
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PostPost by: adigra » Wed Apr 14, 2010 12:47 am

This thread was resurrected as if you guys had read my mind. I'm having these exact problems, but have the original Girling servo. About once in 6-7 times the brake pedal gets very hard, and about the same times the brakes stick. The car has suffered over a decade in a damp garage, so I'm sure the servo has suffered. Sue Miller quotes over ?200 to refurb it, so I am looking for a replacement instead as they seem to go for cheaper than that in new or as new condition.

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PostPost by: alexblack13 » Wed Apr 14, 2010 7:21 am

Have the refurb /overhaul kits disappeared from sale? I had two at one time and rebuilt the servo on my s130. NOT a difficult job by the way, a couple of hours on the bench will fix it. Susan offering a refurb service would suggest the kits are available.Why not get one and get on with it Adi. Or is it going off to get done whilst you do something else?

Fair enough in that case. I must have a look see if the kits are available.. Keep me from boredom in my retirement. :lol: :lol:

Just got set up for machining drums (Brake ones that is)..1st job is a pair of Lambretta ones. I'm nervous as they are not replaceable!! :shock:

Hey ho.... :wink:

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PostPost by: adigra » Wed Apr 14, 2010 9:20 pm

Alex, they are available, but at ?125 I was wondering if it would be more time and cost effective to exchange it for not much more.

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PostPost by: alexblack13 » Wed Apr 14, 2010 9:45 pm

Struth!!.. I see what you mean! I think I remember paying something like 40quid for the two!! Thought that was dear!!

OH well...

Keep well away from the cheepo pattern stuff.. I bought some 'Girling' parts off epay & the photo thereon was of a nice Girling box. Nah! they were from the far east, and not good quality. So I sent them back. The guy is still using the Girling box in his listings though :shock:

Adi.. You will have a pm soon regarding diff...

Alex...
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