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-   -   Throttle pedal (https://madabout-kitcars.com/forum/showthread.php?t=5993)

mcramsay 20th June 2016 18:39

Throttle pedal
 
Has any one tried redesigning the marlin throttle pedal? I am not really keen on the way it mounts on the pedal box... Basically a bolt going through the pivot point in the pedal, my pedal is a really sloppy fit it pedal has been drilled to 12mm but the bolt is m10, meaning the pedal rocks side to side. Then you have the issue of if you tighten the securing bolt too much the pedal then binds...

I have thought about adding a needle bearing thrust washer either side of the pedal pivot point, one of these https://www.ebay.co.uk/ulk/itm/161113406154

This would allow you to clamp up the pedal assembly to stop any lateral movement but still allow it to operate without binding. I have purchased some 10mm ID x24mm OD x 2mm thickness of the above bearings just to see it it will work...

Annoyingly the mounting bolt is welded onto the pedal box and will be too short with the extra 4mm , so I will have to try to grind the bolt out with the pedal box in situ....

MartinClan 20th June 2016 20:30

I used the Marlin throttle pedal with no problem. It sounds like you have a typical Marlin quality issue...
Would it just not be easier to get a thin sleeve made up to take up the slack?

It's going to be pretty difficult to do anything with the box in situ - there ain't much room down there...

Cheers Robin

Mike 20th June 2016 21:07

Quote:

Originally Posted by mcramsay (Post 80384)
Has any one tried redesigning the marlin throttle pedal? I am not really keen on the way it mounts on the pedal box... Basically a bolt going through the pivot point in the pedal, my pedal is a really sloppy fit it pedal has been drilled to 12mm but the bolt is m10, meaning the pedal rocks side to side. Then you have the issue of if you tighten the securing bolt too much the pedal then binds...

I have thought about adding a needle bearing thrust washer either side of the pedal pivot point, one of these https://www.ebay.co.uk/ulk/itm/161113406154

This would allow you to clamp up the pedal assembly to stop any lateral movement but still allow it to operate without binding. I have purchased some 10mm ID x24mm OD x 2mm thickness of the above bearings just to see it it will work...

Annoyingly the mounting bolt is welded onto the pedal box and will be too short with the extra 4mm , so I will have to try to grind the bolt out with the pedal box in situ....

We have all had the same problem - I made all new pedals with 10mm ID needle roller bearings, and welded cut to length 10mm bar in to a 10mm head and thread to make a true 10mm spindle for a perfect fit
I then added a second pedal box support for both the accelerator and clutch pedals to turn the crappy cantilever supports into a stable 2 point pivots; this had the dual benfit of smoother movement, and eliminating lateral movement.

https://farm3.staticflickr.com/2489/...51ec83_z_d.jpg

https://farm3.staticflickr.com/2082/...b45c58_z_d.jpg


https://farm4.staticflickr.com/3406/...fc93c1_m_d.jpg

https://farm3.staticflickr.com/2657/...ac712e_z_d.jpg

mcramsay 20th June 2016 21:56

Looks like I am heading in the correct direction then. I already added a second mount for the clutch, at that time I didn't see the throttle causing any issues. I cut the top section off the throttle pedal as it was so long that the pedal had 20mm of travel from idle to full throttle. It would be very sensitive. So by decreasing the pedal ratio it there is now around 3 inches of pedal travel. I think I will also have to put a return Spring on the pedal. It all feels slightly sluggish. Hopefully my new bearings should do the job

Grey V8 Pete 20th June 2016 22:50

I am currently fitting a new clutch master cylinder to my Hunter. In spite of cutting a second access hole in the top of the bulkhead it is still a nightmare to get at. OK to remove but reassembly looks like tomorrow it will try my patience (and back) to the limit!

I have always had a lot of sideways movement in the clutch pedal and the strip down reveals that although the standard Sierra top hat plastic bushes have been used there was about 0.5mm clearance on diameter between them and both the pedal cross tube and the mounting bolt / sleeve!

I have spent a few hours today rolling up shim stock to try and improve things. Ideally I would like to have a couple of bronze bushes made up but need to get the job done before Castle Combe this Saturday so no time to take the pedal box out either. Oh to have a lathe of my own! There was also no locknut behind the clevis so that was not very secure either! Peter.

mcramsay 21st June 2016 16:40

I cut a rather large access panel on the side of the bulk head by the accelerator. Hopefully I will be able to make it all work. I might get away with the original welded in bolt. I will have to wait and see

Grey V8 Pete 21st June 2016 19:48

I already had a large access panel in the side of the bulkhead and thought that with my extra one on the top I would be good to go. Alas no! There is no way to get a spanner on the top clutch m/cylinder bolt without cutting yet another access hole! Why Marlin didn't just have a complete removable top panel over the whole area beats me. If it was thick steel and the edge of the "hole" was reinforced with extra angle to take a ring of captive nuts it would be plenty strong enough.

For anyone else doing this job remember to fit the top m/cyl bolt to the flange before fitting the banjo fluid connector as it won't go in afterwards! :cry:

mcramsay 21st June 2016 20:27

Yea I have to agree the pedal box was not designed for any kind of maintenance. I had to take the whole thing out the other week. Nightmare. Dash panel off, steering column out and then finally the pedal box out... A huge amount of work.

I had a little play tonight, nipped the pedal bolt up slightly and added a return Spring. Feels much much better so I might leave the bearing mod for now! Just need to add a pedal stop.

Then all I have left is to sort out the air inlet pipe, and bolt up the body work up for good. Bring on the IVA

Patrick 22nd June 2016 19:17

Pedal box is terrible, I'm having all sort of issues with the clutch. I originally added needle bearings to all the pedals (from the E30 pedals) which massively improved it:

http://www.msportster.co.uk/gallery/...truction20.jpg

http://www.msportster.co.uk/gallery/...truction24.jpg

I've been looking through options to completly replace it but the aftermarket is targeted at racers with manual brakes.

morris 25th June 2016 09:17

I had similar concerns about how the accelerator and clutch pedals flopped around so used longer bolts to go through the sides of the chassis and make things more secure. Some photos and descriptions if you look around this area on my flickr page.

https://www.flickr.com/photos/580680...7626910079218/


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