Mcleod Master cylinder Theory.
12-13-2002, 07:39 AM
#1
Mcleod Master cylinder Theory. I just installed the Mcleod Master cylinder and a new Slave along with the SPEC stage 3.
I am having the same Problem that others were having in here.
I have been in contact with Jason from Thunder racing in Baton Rouge And Dave from Nitro Daves in Waco Texas. Two Awsome Guys that have been Very supportive.
Workin with Jason who seems to know more about this problem than anyone I have spoke too, I might have come up with some sort of an answer.
I will just post the email I wrote to him here.
Good Morning Jason
This is Tom Wise in Austin Texas.
We talked about the Mcleod Master cylinder yesterday.
I think I might have a theory on this problem.
I'll try to explain it here.
As I was diving into work this morning I was having the problem again.
Alot worse than yesterday. With all the parts cold soaked from the night,(this seems to make things even worse) I was Barely able to do the short pumps at the top of the stroke to get peddle pressure back.
Now I'm starting to feel that what is happining is this.
The Piston inside the MC has the rubber cup on the end of it that presses against an Spring. When you press down on the peddle this Seal, or rubber cup has to pass the hole leading up to the resevour before it can start applying pressure to the slave. I'm thinking that some how, it is not catching everytime once it passes this point and fluid is just passing around this cup for some distance. This would explain the fact that we are not loosing fluid. It is mearly passing around this seal and going into the resevour.
This could be caused by one of two reasons. 1 There is some out of roundness in the MC walls from welding. Or a faulty Seal (the cup shaped one).
As I described before . Inside the master is an aluminum Plunger. At one end (nearest the Pedal) there is a plain O-ring. Unlike the stock master that has a Cup shaped seal.
At the Business end of this Aluminum Plunger there is the seal that is cup shaped. It floats Free in the cylinder and is being pushed against a Spring that has a metal piece with a shape that looks like it should fit loosely in the rubber cup seal.
I'm guessing to help hold the shape of the seal when the peddle is released.
I hope I'm helping here and not Hendering.
Thanks for all of your support on this problem
Tom Wise
<small>[ December 13, 2002, 08:08 AM: Message edited by: Bugsquawsher ]</small>
I am having the same Problem that others were having in here.
I have been in contact with Jason from Thunder racing in Baton Rouge And Dave from Nitro Daves in Waco Texas. Two Awsome Guys that have been Very supportive.
Workin with Jason who seems to know more about this problem than anyone I have spoke too, I might have come up with some sort of an answer.
I will just post the email I wrote to him here.
Good Morning Jason
This is Tom Wise in Austin Texas.
We talked about the Mcleod Master cylinder yesterday.
I think I might have a theory on this problem.
I'll try to explain it here.
As I was diving into work this morning I was having the problem again.
Alot worse than yesterday. With all the parts cold soaked from the night,(this seems to make things even worse) I was Barely able to do the short pumps at the top of the stroke to get peddle pressure back.
Now I'm starting to feel that what is happining is this.
The Piston inside the MC has the rubber cup on the end of it that presses against an Spring. When you press down on the peddle this Seal, or rubber cup has to pass the hole leading up to the resevour before it can start applying pressure to the slave. I'm thinking that some how, it is not catching everytime once it passes this point and fluid is just passing around this cup for some distance. This would explain the fact that we are not loosing fluid. It is mearly passing around this seal and going into the resevour.
This could be caused by one of two reasons. 1 There is some out of roundness in the MC walls from welding. Or a faulty Seal (the cup shaped one).
As I described before . Inside the master is an aluminum Plunger. At one end (nearest the Pedal) there is a plain O-ring. Unlike the stock master that has a Cup shaped seal.
At the Business end of this Aluminum Plunger there is the seal that is cup shaped. It floats Free in the cylinder and is being pushed against a Spring that has a metal piece with a shape that looks like it should fit loosely in the rubber cup seal.
I'm guessing to help hold the shape of the seal when the peddle is released.
I hope I'm helping here and not Hendering.
Thanks for all of your support on this problem
Tom Wise
<small>[ December 13, 2002, 08:08 AM: Message edited by: Bugsquawsher ]</small>
12-13-2002, 08:49 AM
#2
Re: Mcleod Master cylinder Theory. Thats a good theary!!
I'm kinda surprised with how many people have this problem.I've never had a problem with my Mcloud or the few I installed for other people.Maybe the cylinder is not perfectly round or something like that?
I'm kinda surprised with how many people have this problem.I've never had a problem with my Mcloud or the few I installed for other people.Maybe the cylinder is not perfectly round or something like that?
12-13-2002, 09:04 AM
#3
Re: Mcleod Master cylinder Theory. Just a few minutes ago I was talkin to a friend and Mulling it over in my head.
If the cylinder is round and some how the Port that goes up to the resevour is not Debured correctly or has just too sharp of an edge.
This could over a short time start shaving an knotch out of the Main seal. Its a possibilitie
Its coming out of the car again this afternoon and I will check this out.
The reason I say this is.
Yesterday Late . I had the master out again and bench bled it again. This time I was letting the fluid come out into a bowl instead of just letting it pour into a trash can.
I rememeber seeing little Black Particals in the bowl . And for some stupid reason didn't think about what they were at the time.
I will keep yall posted.
Tom
If the cylinder is round and some how the Port that goes up to the resevour is not Debured correctly or has just too sharp of an edge.
This could over a short time start shaving an knotch out of the Main seal. Its a possibilitie
Its coming out of the car again this afternoon and I will check this out.
The reason I say this is.
Yesterday Late . I had the master out again and bench bled it again. This time I was letting the fluid come out into a bowl instead of just letting it pour into a trash can.
I rememeber seeing little Black Particals in the bowl . And for some stupid reason didn't think about what they were at the time.
I will keep yall posted.
Tom
12-13-2002, 03:42 PM
#4
On The Tree
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Re: Mcleod Master cylinder Theory. After reading all the horror stories about the McLeod adjustable master cylinder, there is no way I'd ever use one. But since all the hi-po clutches seem to require one, what are my other options?
12-14-2002, 04:49 PM
#5
The Bull
Re: Mcleod Master cylinder Theory. That's a fair assessment. I'm acutally going to ditch my entire McLeod setup for the Spec Stage 3 just because of all this crap. It's a good idea to have an adjustable master, but the damn thing is an outrageous pain in the ***. I've even done the rebuild and noticed the same things that you have as well.
12-14-2002, 09:57 PM
#6
Re: Mcleod Master cylinder Theory. Unless you can get inside the master with some sort of a tool that you can round the edges of the two holes that go to the reservoir , you are wasting time and money on rebuilds. I have a machine shop in my office, I think I might try and make a new rod for my stock master and make it adjustable.
Tom
Tom
12-15-2002, 12:07 AM
#7
Re: Mcleod Master cylinder Theory. I have pretty much concluded my tests.
This morning I put My Old Stock Master cylinder back in. I took it for a 1 hour test drive.
I had a steady peddle 100% of the time on this drive.
Now with all the bleeding and rebleeding of this Mcleod, I ended up with Brake Fluid On my New SPEC Disk. I was assured by a Tranny shop that this would Burn or dry off in time.
Or I could pull the tranny and clean it.
I'll let it dry on it's own for now.
On this test drive I found a Lonely Back road with zero traffic. I did a couple of Launches from full stop all the way through 4th gear.
The Clutch engages perfectly every time.
So Yes, the stock Master will work on at least the SPEC Stage 3 with out any Spacers.
On inspection of the Mcleod Master
I found that there was considerable wear on the main seal due to its passing over the two holes that lead up to the reservoir.
I could reach these holes with my finger and they don't feel very smooth. In my opinion they need to be chamfered some how.
The wear on the seal was on one side and more toward the rear of the seal. This damage looks to be occurring on the up stroke. This is making little particles of rubber that get caught up in the leading edge of the seal and cause it to give the erratic peddle positions by letting fluid bypass the seal for a distance, till the rubber particle gets pushed out of the way or gets compressed enough to seal.
I hope this makes since to you.
Tom
<small>[ December 14, 2002, 12:17 PM: Message edited by: Bugsquawsher ]</small>
This morning I put My Old Stock Master cylinder back in. I took it for a 1 hour test drive.
I had a steady peddle 100% of the time on this drive.
Now with all the bleeding and rebleeding of this Mcleod, I ended up with Brake Fluid On my New SPEC Disk. I was assured by a Tranny shop that this would Burn or dry off in time.
Or I could pull the tranny and clean it.
I'll let it dry on it's own for now.
On this test drive I found a Lonely Back road with zero traffic. I did a couple of Launches from full stop all the way through 4th gear.
The Clutch engages perfectly every time.
So Yes, the stock Master will work on at least the SPEC Stage 3 with out any Spacers.
On inspection of the Mcleod Master
I found that there was considerable wear on the main seal due to its passing over the two holes that lead up to the reservoir.
I could reach these holes with my finger and they don't feel very smooth. In my opinion they need to be chamfered some how.
The wear on the seal was on one side and more toward the rear of the seal. This damage looks to be occurring on the up stroke. This is making little particles of rubber that get caught up in the leading edge of the seal and cause it to give the erratic peddle positions by letting fluid bypass the seal for a distance, till the rubber particle gets pushed out of the way or gets compressed enough to seal.
I hope this makes since to you.
Tom
<small>[ December 14, 2002, 12:17 PM: Message edited by: Bugsquawsher ]</small>
