Lotus Elan

MOT fail, handbrake imbalance

PostPost by: oldelanman » Fri Mar 04, 2011 9:11 am

types26/36/74 wrote:
Galwaylotus wrote:It's called a decelerometer and is used when a vehicle can't be tested on the roller brake tester. :wink:

The Decelerometer ....Oh yes, back in the late 60's I used to do MOT's and we had this heavy wooden box that contained this round device, if I remember correctly we would set it to level, set to zero, and at a given speed slam on the brakes, take the reading then repeat on the handbrake.
Well it read in % but it was not unusual for it to go past 100% so I suppose theoretically we had stopped and started going backwards...........well that never happened :lol:
Seriously though it was a very crude device and you could make it read what you wanted....surely times have moved on and I havent seen one in years.

I think you are talking about the Tapley meter and they are still made. I used these in the 70's and the meter itself is very accurate and easy to calibrate, one problem was they tended to slide on the floor under braking and if you kept the brake applied until the vehicle actually came to rest it would record the final lurch as peak deceleration - useful sometimes if the brakes were not too good !
There were other devices which worked on the same principal of a suspended mass - Motometer recorded decel and also pedal effort on a paper chart and Bowmonk (also made by Tapley I think) which was a small 2" gauge which simply stuck to the windscreen.

All of these were sophisticated devices compared with the housebrick which I have also seen used - on it's side for service brake and on it's end for handbrake - if the brick falls over under braking the performance is OK.

Sorry this is getting a bit off topic now.
Tapley meter.JPG and
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PostPost by: paddy » Fri Mar 04, 2011 10:01 pm

Problem solved .. hopefully.

One of the pads had lots of crud in the "hook" so wasn't sitting flat against the disc - so it was only contacting the disc for about 30% of its area. As the pad wore down, there was obviously less and less contacting the disc. I put in some old half-worn (but straight) pads and hopefully I can get it passed without having to wait for new replacements.

Thanks again for the suggestions.

1963 Elan S1
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