Brake servo - faulty?

[106500]

I own a Stromberg Elan S4. I've just revamped the brakes (new flexible connections, discs, pads, etc. I had no problem with bleeding. The issue I have is that the servo (a Lockheed unit) appears to be giving little or no assistance (not that I can detect anyway). I have to apply plenty of pedal pressure when braking. The vacuum pipe to the servo is fine and when I remove the filter there appears to be plenty of vacuum there. I guess I'm uncertain as to just how much assistance a servo should provide to braking on the Elan. Is there anything else I can do to check the condition of the servo? - I'm reluctant to replace it (cost)! until I'm certain it has failed. I would be very grateful for any comments. Thanks.

[Elanintheforest]

A strange coincidence, as I recently bought a Stromberg S4 with Lockheed servo...and that provides no assistance either. The brakes feel dead, and a lot of effort is required to slow the car down.
My S3 with original Girling feels totally different, with pin-sharp braking...quite easy to lock the wheels, but not without trying...they feel just right.

I bought a 2nd hand Girling, and took it to Classicar Automotive at the Stoneleigh show, who said that a lot of folks are having problems with the Lockheed and are going back to the original. There is a known problem with the Lockheed whereby the brakes will go on, but not realease, and Classicar Automotive have solved this with a different spring somewhere in the mechanism. But this isn't the problem with my servo...it just doesn't seem to work.

Bottom line is that the brakes on an Elan feel almost as good as a modern car. If it's not the servo, the most obvious next thing to look at are the pads...if they are too hard (or racing pads) they also would feel pretty dead until really warmed up, which they probably wouldn't do in normal road usage.
Mark

[neilsjuke]

Are you using Silicone fluid Lockheed do not recomend it's use .

[rgh0]

Modern high coefficent of friction pads provide an Elan with better brake performance and similar pedal pressures without a booster that the boosted versions provided when orginal

I would get rid of the booster and get new front pads such as Ferodo DS2500 or EBC Green both of which work very well from cold in a road car. Staying with conventionalpads at the rear such as EBC black also help balance up the brakes better as the rear tends to lock up first on an Elan with same pads front and rear.

cheers
Rohan