brake help needed


Information and questions on GL1100 Goldwings (1980-1983)
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1fastgl1100
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Location: Ocala, Florida
Motorcycle: 1983 GL1100A and 1982 GL1100A Modified

brake help needed

Postby 1fastgl1100 » Fri Feb 07, 2014 4:10 pm



Is there any difference between the "FRONT" master cylinder on the 1982 and the 1983 GL1100A's I am thinking the piston size in the 83's master cylinder may be smaller since it operates only one caliper while the 82's master cylinder operates 2 calipers.
Reason I am asking my wife who tends to ride the 1983 GL1100a (with a voyager kit aka training wheels) is having a hard time depressing the rear brake (she has medical issue which is why she has the training wheels) and I have heard there is a way to link all the calipers to work off the front master cylinder for handicap braking. yet, I have not heard if the master cylinder needs to be replaced or with what upgraded part.
what I was thinking was going to a HD or Boss Hoss master cylinder but those are for 1" bars and not sure they would work for pushing that much fluid.

any ideas.... if cant come up with something she may have to quit riding and stick with the cage.



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RBGERSON
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Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: brake help needed

Postby RBGERSON » Sat Feb 08, 2014 7:37 am

Yep, you'll need a larger master..as the brakes pads wear down you'll need to push more fluid. With new pads you might be OK..but as they wear the standard master won't have enough travel/fluid to work all three to their max extension/pressure.
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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WingAdmin
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Re: brake help needed

Postby WingAdmin » Mon Feb 10, 2014 12:20 pm

RBGERSON wrote:Yep, you'll need a larger master..as the brakes pads wear down you'll need to push more fluid. With new pads you might be OK..but as they wear the standard master won't have enough travel/fluid to work all three to their max extension/pressure.


That's not really true. As the pads wear, the pistons don't retract to their original position, otherwise you would have to pump several times to get any brakes. When you apply brakes, the pistons apply pressure to push the pads against the discs. When you release brakes, miniscule runout on the discs push the pads (and pistons) back into their bore, but only an extremely small amount. As the pads wear, the pistons gradually come out more and more, and stay out - until new pads are put on, when they are fully retracted again.

The amount of fluid pushed as the pads wear remains constant. The biggest problem you'll have with using a single lever to run more brakes is that you lose your mechanical advantage. It will be much tougher to squeeze the brakes to get the same amount of braking.

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RBGERSON
Posts: 2612
Joined: Tue Mar 09, 2010 7:57 am
Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: brake help needed

Postby RBGERSON » Tue Feb 11, 2014 7:53 am

Yep..I didn't think it through..:(!!
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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Phavas
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Location: Maine
Motorcycle: 1976 GL1000 x 2, 1977 GL1000 x 3, 1981 GL1100 Sidecar, CB750 K8 CB 550 K8, 1954 Velocette MSS, 1937 Velocette KSS, 1932 Norton 16, 1946 AJS 18, 1948 Vincent Rapide, BMW R 100 RT1, BMW GS 80, BMW R60/7, 1936 Halcyon 50, 2003 Triumph Trophy 1200, 1994 Honda CB750 twin cam and still looking...

Re: brake help needed

Postby Phavas » Fri Feb 14, 2014 5:09 pm

Fluids are not compressible. To get the front and rear brakes to work in coordination (not Synch) you need a proportioning valve if you're having trouble stopping - look into Moto Guzzi..
This will reduce the flow forward or aft and delay the fluid pressure on one or the other by a fraction. The idea is simply to delay the fluid travel by a little bit to allow the front or rear brake to come on first. After they are both on, they will both apply the same amount of pressure on their respective discs. Ergo: when the front disc is applied first, it will continue to slow the bike at the same rate continually. When the rear brake comes on it will supplement the front brake but apply the same pressure slowing the bike evenly. This isn't rocket science, it's fluid dynamics and they're regulated by pretty simple laws of physics: input = outgo.

Cheers,
Zaphod
Writing roughshod over the English language

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Phavas
Posts: 60
Joined: Mon Feb 10, 2014 10:02 pm
Location: Maine
Motorcycle: 1976 GL1000 x 2, 1977 GL1000 x 3, 1981 GL1100 Sidecar, CB750 K8 CB 550 K8, 1954 Velocette MSS, 1937 Velocette KSS, 1932 Norton 16, 1946 AJS 18, 1948 Vincent Rapide, BMW R 100 RT1, BMW GS 80, BMW R60/7, 1936 Halcyon 50, 2003 Triumph Trophy 1200, 1994 Honda CB750 twin cam and still looking...

Re: brake help needed

Postby Phavas » Fri Feb 14, 2014 5:12 pm

As an aside: it requires no more fluid to actuate worn pads than new pads. The amount of fluid displacement is the same. Too often people top up brake fluid which is useless if the system is intact. Fluid drop is a visual indication of pad wear.
Brake fluid should be replaced every year as it is anhydrous but oxidizes and absorbs moisture form the atmosphere (soft pedal syndrome).

Cheers,
Zaphod


Writing roughshod over the English language


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