Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Roadster brakes - a question of feel

Thank you John for this info. I was thinking of dropping the brake pedal back a bit by adjusting the rod, as it seems a fair way forward of the throttle on the Roadster, but I can now see it will need more careful consideration before I touch this.. I see that the angle position of the pedal arm as it passes through its arc of travel will have an impact on both cylinder pressure and rod travel distance. So as you describe moving the pedal further back will impact the master cylinders operation. Hmmm.. some further thought needed on this.

The other consideration is driving position Dave. Not being long in the leg there is a limit to how far I can slide the seat back to avoid being too close to wheel. Although this compromise is mainly geared to clutch operation I woudn't want the brake pedal any further forward. TBH I can heel and toe OK with present setup quite adequately as is.

Hi Richard ref driving position. I am 6ft and long in the leg, so my seat is as far back as it will go and as raked back to max. The driving position is not so bad, but I need to move my right leg backward to go from throttle to brake. On the clutch side, the pedal is a long heavy throw which I am ok with, the clutch bites quite high up in the pedal movement, so there may be scope here to adjust the pedal position back a little. When not using my clutch leg/foot I place the leg in a slight bend onto the transmission tunnel, with the foot just behind the pedal, which is acceptable.
In the years before I retired I undertook a lot of design work on exploration ships, so my mind is always looking at ways to improve known problem areas, its a difficult thing to stop doing....hence all my questions so quickly on this forum. I have learnt not to reinvent the wheel though.. that's why the forum is a great place to ask first..

Dave,
I had Cain at Wolf Performance make me an adjustable throttle pedal as I had the same issue. He has some available if you are interested.
John

Thanks John, chatted to Cain this morning, so will give the adjustable pedal a go. On my car Morgan must have assembled the pedal to the throttle sensor before assembly in the car, as the pedal securing bolts can not easily be withdrawn due to lack of clearance on the body side... if the bolts had been positioned the other way round it would have been a breeze.

Good luck it is in a difficult to reach location but the result is well worth it.

Interesting that Bob, may give it a try

It would appear that Ceratec grease is mineral based and although good on metal to metal contact, ie brake pads, it is best avoided on rubber. Do we always know whether piston dust seals are rubber or synthetic? Red rubber grease may be better under the dust covers.

Well, over the weekend I pulled out the clutch/brake pedal box on our 3.7 Roadster, to check out the brake and clutch pedal position adjustments at the pedal arms to master cylinder rods and also to make a new clevis pin for the clutch pedal arm, as it was fairly worn ( at only 9K miles).

What was found is as follows:

Brakes..
The brake master cylinder actuating rod is adjusted at the pedal arm by means of a threaded section of rod through the clevis that connects the brake pedal arm to the master cylinder rod. The rod was found to have been adjusted so that the rods threaded section was through the clevis to the extent that it touched the pedal arm, this meant that as the brake pedal arm went through its arc of travel when depressing the pedal, the rod locked up the clevis and stopped it swivelling on the pedal arm at approx 3/4 through its operational arc, when this happened the pedal arm pushed the master cylinder rod downward at the same time the rod was trying to move forward and actuate the m/cylinder, this produced a semi binding of its movement. The fix was to remove approx 4mm off the end of the threaded section of the rod using a dremmel cutting disk... This allowed further adjustment of the pedal position and allowed working clearance between rod and the brake pedal arm.
Note:- Operation of the brakes must be checked after any adjustment of the brake pedal arm.

Brake return spring.. The brake pedal spring as used appears coil bound.. i.e. As the brake pedal arm is operated it gives tension to the brake pedal return spring, but its coils are already touching each other and bind into each other as the brake pedal goes through its travel and the spring rotates. By pulling the spring coils gently apart ( using a fair amount of leverage ) slightly beyond their elastic limit, the spring coils can be set 2mm apart, this means that as the pedal spring is wound by operating the brake pedal the coils have clearance to move towards each other.

The result of the above two adjustments have made a big improvement of the brake pedal feel.
The next job is to clean the front brake pads in hot soapy water or replace the pads, most likely I will try to clean first..

Clutch.
While the pedal box was out I made a new clevis pin on the lathe for the clutch pedal arm, the original clevis pin had worn so that it had about 15mm of slop in the clutch pedal arm. All moving parts for the clevis are now greased with high pressure grease.. Interestingly the brake pedal clevis pin is larger than the clutch clevis pin, this gives a much larger surface area to transmit the force.. The Brake clevis pin was not worn at all!.

I had previously fitted the Wolf Performance Roadster 3.7 adjustable throttle pedal, the end result with an adjustable throttle pedal and tweaked positions of brake and clutch pedals has transformed what was a poor driving position.

Good work Dave, particularly the adjustable brake actuation rod.