MTW Posted June 2, 2022 Share Posted June 2, 2022 I have just fitted a high effort brake pedal to my 420r, I was hoping for a firmer pedal with less travel to make heel and toe a little easier.but I have just fitted the pedal and the shim for the master cylinder and if anything the pedal feels softer and longer than before? Just wondering if I have done something wrong?when I fitted the master cylinder shim it made the new pedal sit about an inch further forward than before (as you can see by how far away the brake light switch is in the picture)so to get the pedal back to the right position I had to set the master cylinder push rod to maximum where it attaches to the top of the pedal, so there is no more adjustment there. the pedal sits in the right place, but like I say it seems to be even softer than the standard pedal and even harder to heel and toe?the only thing I can think of is the shim is actually nullifying the extra pivot length of the high effort pedal? Making it the same or worse than the stock pedal? I'm thinking to maybe remove the shim re adjust and see how that feels? Even though the piston push rod would be at an angle? Any thoughts much appreciated! Link to comment Share on other sites More sharing options...
Wrightpayne Posted June 2, 2022 Share Posted June 2, 2022 Edited - its the shim altering the M/C angle!! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 2, 2022 Member Share Posted June 2, 2022 Link to comment Share on other sites More sharing options...
ScottR400D Posted June 2, 2022 Share Posted June 2, 2022 #2 I think he knows that, but without it the travel of the actuating rod from the new pedal would be at an angle to the actual cylinder. I wouldn't remove the shim until all other avenues are exhausted. Did you disconnect any pipes to fit the shim or pedal? Are you sure it's all bled properly? Link to comment Share on other sites More sharing options...
MTW Posted June 2, 2022 Author Share Posted June 2, 2022 Yes for sure! In my limited mind I was just thinking, the pivot point to the piston connection is about 10mm longer on the high effort pedal, the shim pushes the master cylinder back about 10mm, then you have to adjust the pedal connection to the piston 10mm to get the pedal right, I'm just thinking maybe that all cancels out the extended pedal somehow.I have seen a DPR car posted on here with the pedal, but the master cylinder looks like it doesn't have the shim. But I have asked for clarification from them.maybe the Bigger AP master cylinder is a bit more sophisticated and can run fine with the piston at an angle? Compared to the standard cylinder, the shim looks like it's made to fit a master cylinder a lot smaller than the AP. Link to comment Share on other sites More sharing options...
MTW Posted June 2, 2022 Author Share Posted June 2, 2022 And no didn't disconnect any pipes, and the brakes were fine with the old pedal. It probably feels exactly the same brake power wise but the new pedal seems to require a lot less effort and seems to have slightly more travel, which is the opposite effect to what I thought it would have! Link to comment Share on other sites More sharing options...
MTW Posted June 2, 2022 Author Share Posted June 2, 2022 Thanks for the the pic edit Jonathan! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 2, 2022 Member Share Posted June 2, 2022 : - )Jonathan Link to comment Share on other sites More sharing options...
ScottR400D Posted June 2, 2022 Share Posted June 2, 2022 #6 I don't have the HE pedal but that's exactly how it should be, less movement at the foot, more effort. Have you adjusted out any free movement of the assembly? Link to comment Share on other sites More sharing options...
MTW Posted June 3, 2022 Author Share Posted June 3, 2022 No I didn't change any of the free play at all, the only adjustment I made was I had to extend the the pedal to piston rod mount to the maximum the the threads would allow to get the pedal position correctly Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted June 3, 2022 Leadership Team Share Posted June 3, 2022 Just checking; you do have both parts of the shim installed, don't you? One either side of the mounting surface? I couldn't see the front-most shim on your photos.James Link to comment Share on other sites More sharing options...
MTW Posted June 3, 2022 Author Share Posted June 3, 2022 Another shim? This is the only one I have fitted. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted June 3, 2022 Leadership Team Share Posted June 3, 2022 Ah, right. They should be fitted in pairs (you need to buy two).Works very effectively on my car. I'll see if I have any images (not near car atm).James Link to comment Share on other sites More sharing options...
ScottR400D Posted June 3, 2022 Share Posted June 3, 2022 Interesting. What does the other half do? Makes the assembly parallel for the bolts presumably? Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted June 3, 2022 Leadership Team Share Posted June 3, 2022 Sorry - can't find a photo at present. But as posted above, they ensure that the mounting bolts are torqued up square to the mounting surface. Without the second shim, I'd say there's a risk the MC is neither securely mounted nor correctly positioned. Either way, it's incorrect without the second half of the pair!James Link to comment Share on other sites More sharing options...
ScottR400D Posted June 3, 2022 Share Posted June 3, 2022 Yes, that makes sense. Link to comment Share on other sites More sharing options...
MTW Posted June 3, 2022 Author Share Posted June 3, 2022 Ah I see, yes that makes sense completely!I will get another ordered, yes if you are able to get a photo it would be great, also I would be interested to see where your pedal attaches to the pushrod, I had to adjust mine right to the end of the thread ti get the pedal back in line with the clutch pedal. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted June 3, 2022 Leadership Team Share Posted June 3, 2022 Away at present so it will be a week or so before I can take a new photo. I don't remember anything odd about the rod adjustment. So long as the clevis is still secured to the threaded shaft with full lock nut engagement, it doesn't really matter if the full rod length is needed.James Link to comment Share on other sites More sharing options...
MTW Posted June 3, 2022 Author Share Posted June 3, 2022 Ok no worries, I will get another ordered and fitted, makes perfect sense, hopefully that will make the difference.I might look at trying to move the throttle pedal further back after that if it's still not 100% on the heel and toe front Link to comment Share on other sites More sharing options...
MTW Posted June 7, 2022 Author Share Posted June 7, 2022 Just to update, I did order another shim to fit.but a few days ago I emailed DPR racing because I had seen one of their builds that had the high effort pedal but it looked like there was no shim fitted to the master cylinder, I asked them if this was the case and that I was having the opposite effects of what I thought the brake pedal should feel like.their response was bellow. maybe the shim is too much angle? It looks about half of the angle with washers instead of the shim, In any case if it's good for DPR it's good for me! I will give the washers a go and see how I get on. 1 Link to comment Share on other sites More sharing options...
ScottR400D Posted June 7, 2022 Share Posted June 7, 2022 Interesting! Let us know how it goes. Link to comment Share on other sites More sharing options...
Nigel B Posted June 7, 2022 Share Posted June 7, 2022 DPR fitted a high effort pedal to my car last year when I was having the suspension set up. They did use washers rather than the shims & the pedal travel has been reduced considerably.I much prefer the feel. I'd go as far as to say it's the best modification I've made to the car & that's saying something, given I've also had RBTBs fitted! I'd assumed they'd fitted the washers as they'd run out of shims, so it's interesting to hear it's actually a deliberate modification. Link to comment Share on other sites More sharing options...
MTW Posted June 8, 2022 Author Share Posted June 8, 2022 Ah that's good to hear! Yes I hope this sorts the issues.I don't suppose you have a picture of the washers do you? Or a pic of how the pedals are adjusted in the pedal box? Link to comment Share on other sites More sharing options...
DW199 Posted June 8, 2022 Share Posted June 8, 2022 The washer solution looks like a bodge. I don't see how it can be any better than a shim. 1 Link to comment Share on other sites More sharing options...
OldAndrewE Posted June 8, 2022 Share Posted June 8, 2022 Pair of shims £56.50 (more than the actual pedal). I would say that that makes washers an attractive alternative Link to comment Share on other sites More sharing options...
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