Performance Machine Brake Caliper

[twoseas]

I installed a front wheel 6 piston brake caliper made by Performance Machine when I eliminated the right side brake rotor after I installed custom wheels.  I find that the breaking power is almost non existent.  I called PM and they said I needed to check if the master cylinder had a 9/16" bore in lieu of an 11/16" bore for better performance. He believes that the OEM master cylinder should be a 9/16 since it was operating a two caliper/rotor system before and I may need to look at another area for the cause of the poor braking.

Has anyone installed this single 6 piston caliper and experienced this poor braking power ?  If so, were you able to improve the braking performance and care to share how you did it ?

Thanks

[tmwmoose]

what are we working on???

[twoseas]

what are we working on???

2006 Road King Classic

[Mark222]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

[twoseas]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

Mark,

Your explanation falls in line with what I was told by PM.  I didn't realize that there were different MC bore sizes. Is there a way to tell the MC bore size without disassembling the MC ?
Thanks for the heads up.

Ray

[harley_cruiser]

Yes two caliper systems use 11/16 bore. You need the single caliper 9/16.
Hydraulics is all about leverage.

[tommy g]

If you remove your switch housing you'll see the size stamped on the mc.

[twoseas]

Yes two caliper systems use 11/16 bore. You need the single caliper 9/16.
Hydrolics is all about leverage.

Harley_Cruiser,

Thanks for your feedback and photo !

[twoseas]

If you remove your switch housing you'll see the size stamped on the mc.

Tommy g, thanks for the guidance.

[Ajayrk]

A little general advice about selecting bore size in your master cylinder may be helpful. Decreasing MC bore size will decrease your pedal effort and increase your pedal travel. Conversely, a larger bore in your car's master cylinder will, all other components being consistent, increase your pedal effort and decrease your pedal travel. As with some other brake parts purchases, this comes down to your preference for how the brakes "feel" under foot when you are driving.


Tech Talk: Master Cylinder Bore Size Affects Pedal Travel Distance and Effort

July 5th, 2013

[Hossamania]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

I think what you have listed is the opposite, Ajayrk has given the correct scenario.

[PoorUB]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

I think what you have listed is the opposite, Ajayrk has given the correct scenario.

[Mark222]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

I think what you have listed is the opposite, Ajayrk has given the correct scenario.

Yeah, I see I had it backward...   

[twoseas]

A little general advice about selecting bore size in your master cylinder may be helpful. Decreasing MC bore size will decrease your pedal effort and increase your pedal travel. Conversely, a larger bore in your car's master cylinder will, all other components being consistent, increase your pedal effort and decrease your pedal travel. As with some other brake parts purchases, this comes down to your preference for how the brakes "feel" under foot when you are driving.


Tech Talk: Master Cylinder Bore Size Affects Pedal Travel Distance and Effort

July 5th, 2013

Ajaryk,

Thanks for your contribution.

[twoseas]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

I think what you have listed is the opposite, Ajayrk has given the correct scenario.

Hossamania,

Thanks for the clarification.

[twincam8888]

Hey "Two"

I had a similar situation, not exactly the same.  I removed two single-piston calipers on my '91 FLHTCU and replaced them with a pair of 4 piston PM calipers.  Had to change M/C to get the correct travel and firmness = smooth stop and full power.

Also I changed the single piston rear as well with 4 piston PM unit, changed rear M/C to compensate.

IIRC,

1.    Using M/C with smaller bore than needed = hard to pull, very little travel and lack of stopping power transferred to caliper

2.    Using M/C with bigger bore than needed = too much travel, soft lever and you run out of space at the hand grip before max stopping
       power is reached, or perhaps even before pads engage enough to stop.

I am sure others who know more will chime in soon.

Mark

I think what you have listed is the opposite, Ajayrk has given the correct scenario.

[packrat56]

    This might help.



http://www.vintagebrake.com/mastercylinder.htm

[Templar2]

PM 6 piston caliper with Lyndall Gold pads on a 2007 FLSTC, 9/16" MC.  Bike has plenty of stop with that setup so a change in the master cylinder should be sufficient.  Have also gone with a 13" disc setup and that REALLY stopped the bike!   

[Smarty]

What you need is a take off master cylinder from a single side front brake system like off of a softail. I did this on a 2004 Ultra years ago. Works perfect. Should be tons around on eBay from those changing out to chrome controls.