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Fix for those that have the Mcleod Master Cylinder

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Old 02-24-2008, 04:18 PM
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Default Fix for those that have the Mcleod Master Cylinder

I know by reading on this forum alot of other people have been having the same problem with the Mcleod master cylinder on the F-body cars. Inconsisted ingagement point; would ingage high sometimes and other times right off the floor board. Mine would also if pumped real quick several times in a row pedal would start going down to the floor. Know there was no problem with air in the system; pressure bleed system; used the mityvac system and were no air bubbles. Looked at the design of a stock master compaired to the McLeod master and the main difference was the design of the piston assembly inside the housing. So I did some research and found Wilwood brakes makes a rebuild kit with a piston assembly made like the stock master but in the 13/16 inch bore. So I took a chance and orderd the rebuild kit from Summit Racing. Took awhile to get it as it was back ordered; but with shipping it was only around $30 dollars. So I put only the new piston and spring part in. Bleed the system, which is still fun but with the mityvac only puling 5lbs vacum removed all the air out of the system. Got in the car and drove it and it works great. Pedal is easier to push now as the spring inside is alittle weaker. I can also pump the pedal as quick as I want now and the pedal stays consistant unlike before it would start dropping closer to the floor and fill like it had alot of play before it would start to build pressure. SO far I do believe this may be accure for the problem alot of use have been having .
Old 02-24-2008, 04:22 PM
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Default Part number for kit

By the way the Part number of thr wilwwod kit is 260-5921. You can go to the Wilwood web-site and research it some more.
Old 02-24-2008, 10:43 PM
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Interesting, I am having that problem and bought the Mcleod rebuild kit and the problem still didnt go away. Maybe I will try this out. Thanks.
Old 02-25-2008, 01:55 AM
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good find!!!
Old 02-25-2008, 03:44 PM
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Awesome find, I may have to do this in the spring as I just rebuilt the master for the 3rd time in 7 years and it's still 'off'.
Old 03-01-2008, 11:51 AM
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I just put mine in and the bastard doesn't want hold pressure. This unit sucks so far, so I just ordered it and hopefully will fix my problem. Thanks for the info.
Old 03-01-2008, 02:38 PM
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Very interesting. I have a Mcleod master and thought the issue was bad fluid. Maybe I'll try doing this same thing. Any pictures by chance????
Old 03-01-2008, 03:50 PM
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does the wilwood kit work for stock masters or only the mcleod?
Old 03-01-2008, 03:52 PM
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Originally Posted by purdueranger
does the wilwood kit work for stock masters or only the mcleod?
I'm pretty sure the stock master is not a rebuildable piece...only the McLeod.
Old 03-01-2008, 03:52 PM
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Yeah, and the mcleod has the 13/16 bore, the stock is smaller.
Old 03-01-2008, 05:39 PM
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Maybe the spring is the reason why my Mcleod has such a heavy peddle pressure. Does everyone who has a Mcleod master have the same heavy pressure?
Old 03-01-2008, 06:07 PM
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I never considered mine heavy; isn't that more due to the pressure plate on the clutch? I've had this adjustable with 2 clutches now. The RAM980 needed a cinder block to put down, my ClutchMasters in there now is like stock, or close to my 02' Z06 clutch.
Old 03-01-2008, 06:15 PM
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I've driven a 2000 F-body that had a stock clutch with the McLeod master cylinder, and the pedal was heavy as hell. I thought it was a heavy duty clutch until I found out otherwise. I thought it had something to do with the larger bore, but I'm probably wrong on that one...
Old 03-01-2008, 06:18 PM
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Maybe your right and I've just gotten used to after all these years??
Old 03-01-2008, 06:46 PM
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Originally Posted by Viper
Maybe your right and I've just gotten used to after all these years??
Possibly...when I drove a car with an LS7 clutch installed, I damn near put my foot through the floor board It just felt really light...my RPS isn't too bad (in between stock and the Ram I used to run), and the Ram Powergrip I had in before took a pretty good amount of effort.
Old 03-02-2008, 09:29 AM
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I've got the Mcleod master with a Mcleod dual friction single disc, but I forget which pressure plate I have. I'll be checking in the near future when I get my lift. I plan on installing a remote bleader line, and i'll document what I have. Something that I have forgotten to do since I've gotten the clutch.
Old 03-02-2008, 09:47 AM
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Originally Posted by Peppershaker
By the way the Part number of thr wilwwod kit is 260-5921. You can go to the Wilwood web-site and research it some more.
So basically, you've "patched" the McLeod Adjustable MC to run the way that it's supposed to when you buy it.
Old 03-02-2008, 09:54 AM
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^^^I hope this is a good fix. I had to put a stocker in for now and it works just fine. I don't have any of the problems I was having before. I am gonna rebuild the Mcleod and put it back in to see if it will do it's job. If not, now I know the stocker will do just fine. I was really surprised with the stocker since I have a Spec 3, but I think the drill mod really helps the stocker out.
Old 03-02-2008, 11:47 AM
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Well here is a update on the orignal post I started. Have had the McLeod master cylinder back in my car with the Wilwood master cylinder rebuild kit for about a month and it's still working great. Do believe this will cure alot of problems people have been having. Do think pedal is easier to push because spring in the Wilwood kit is not as strong; but it does not need to be. Just be sure you get all the air bleed out and it will work fine. Hope this helps alot of people out.
Old 03-02-2008, 05:39 PM
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i thought the problem with the Mcleod was the orifice on the bore of the master cylinder wasn't correctly machined causing wear to the o rings?


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