Rear Brake fluid

gotojoe · 11-18-2012, 10:04 AM

Rear brake fluid. Pedal getting low ?

There are concerns about the fluid in the reservoir getting hot and some owners have moved the reservoir away from the rear of the engine crank case.

Whilst it isn't a good thing for the fluid to become hot in the reservoir I doubt if it is the primary cause of the pedal getting low.

The reservoir acts as a header for the system and as the pads wear the level in the reservoir will become a little lower.

I don't believe that during the course of a ride out that the brake fluid in the reservoir " mixes" into the brake fluid in the master cylinder as there is no return line as such.

Therefore when during a ride out if my pedal should get low then this is most likely due to heating of the fluid in the MASTER cylinder which sits close to the exhaust pipes. The Master cylinder is not completely shielded from the heat down there and I believe this is the principle area that requires attention and not the reservoir.
I'm interested in other's opinions on this too : )

joe

Donsy · 11-18-2012, 10:09 AM

MV BOY · 11-18-2012, 10:34 AM

I moved my reservoir under my seat and fitted fast road pads to cure my rear brake or lack of rear brake problem but that only helped after curing the problem.........check yr exhaust as mine had cracked round the joint blowing hot gases straight onto the master cylinder. Welded up with additional webbing and problem solved. I now have a rear brake helped by changing the pads and moving the reservoir. Hope this helps!

Sent from my iPhone using Motorcycle.com App

luizfto · 11-18-2012, 11:56 AM

I have replaced original DOT 4 fluid by DOT 5.1.
Brake pedal still lowers, but much less, and rear brake is still operative after a hard ride:

http://www.mvagusta.net/forum/showth...hlight=DOT+5.1

silentservice703 · 11-18-2012, 02:34 PM

I use that special "R" designated brake fluid for the "R"ear brake........

Renaissance · 11-18-2012, 03:25 PM

agree with gotojoe and Donsy and luizfto

mentioned in other posts but I had my exhaust header heatshield replaced with an improved material (larger and thicker version provided by MV) which better shielded the partly exposed m/c in addition to using dot 5.1....problem solved.

mitchy · 11-18-2012, 04:35 PM

Spot-on Joe,thats why I did this,and it helps. Name: 100_1060.jpg
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gotojoe · 11-19-2012, 04:41 AM

But where can I cook my bacon n eggs now ? ; )

11-18-2012, 10:04 AM	#1
gotojoe Senior Member MV in the Registry: [F4 1000 R] [View photo album] Join Date: Nov 2009 Location: Warwickshire UK Posts: 5,432	Rear Brake fluid Rear brake fluid. Pedal getting low ? There are concerns about the fluid in the reservoir getting hot and some owners have moved the reservoir away from the rear of the engine crank case. Whilst it isn't a good thing for the fluid to become hot in the reservoir I doubt if it is the primary cause of the pedal getting low. The reservoir acts as a header for the system and as the pads wear the level in the reservoir will become a little lower. I don't believe that during the course of a ride out that the brake fluid in the reservoir " mixes" into the brake fluid in the master cylinder as there is no return line as such. Therefore when during a ride out if my pedal should get low then this is most likely due to heating of the fluid in the MASTER cylinder which sits close to the exhaust pipes. The Master cylinder is not completely shielded from the heat down there and I believe this is the principle area that requires attention and not the reservoir. I'm interested in other's opinions on this too : ) joe

11-18-2012, 10:09 AM	#2
Donsy Senior Member MV in the Registry: [F4 1000 R] [View photo album] Join Date: Aug 2009 Location: Western Australia Posts: 9,495	Yup __________________ Dons Nel Manuals are here - http://www.teamdouble3racing.com/manuals

11-18-2012, 02:34 PM	#5
silentservice703 Senior Member MV in the Registry: [F4 1000 R 312] [View photo album] Join Date: Feb 2008 Location: In Duxbury, MA, USA with Lee and Patty in my heart. Posts: 6,291	I use that special "R" designated brake fluid for the "R"ear brake........ __________________ *Keep your words soft and sweet...for somday you shall eat them!* A government that robs Peter to pay Paul can always depend upon the support of Paul. -- George Bernard Shaw

11-18-2012, 04:35 PM	#7
mitchy Senior Member MV in the Registry: [F4 1078 RR 312] [View photo album] Join Date: Feb 2010 Location: Gold Coast, Australia. Posts: 2,048	Spot-on Joe,thats why I did this,and it helps. __________________ Mitch The Hub Man Work.Email & Paypal. tweedcitytruck@onestream.com.au Work Phone (+61)0755244655

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11-18-2012, 10:34 AM	#3
MV BOY Senior Member MV in the Registry: [F4 1000 R 312] Join Date: Jan 2012 Location: Stockton-On-Tees, England Posts: 246	I moved my reservoir under my seat and fitted fast road pads to cure my rear brake or lack of rear brake problem but that only helped after curing the problem.........check yr exhaust as mine had cracked round the joint blowing hot gases straight onto the master cylinder. Welded up with additional webbing and problem solved. I now have a rear brake helped by changing the pads and moving the reservoir. Hope this helps! Sent from my iPhone using Motorcycle.com App

11-18-2012, 11:56 AM	#4
luizfto Senior Member MV in the Registry: [F4 MY2010+] [View photo album] Join Date: Mar 2012 Location: S J Campos (SP) Brazil Posts: 62	I have replaced original DOT 4 fluid by DOT 5.1. Brake pedal still lowers, but much less, and rear brake is still operative after a hard ride: http://www.mvagusta.net/forum/showth...hlight=DOT+5.1

11-18-2012, 03:25 PM	#6
Renaissance Senior Member No MVs in the Registry Join Date: Feb 2012 Location: Logan Queensland Australia Posts: 293	agree with gotojoe and Donsy and luizfto mentioned in other posts but I had my exhaust header heatshield replaced with an improved material (larger and thicker version provided by MV) which better shielded the partly exposed m/c in addition to using dot 5.1....problem solved.

11-19-2012, 04:41 AM	#8
gotojoe Senior Member MV in the Registry: [F4 1000 R] [View photo album] Join Date: Nov 2009 Location: Warwickshire UK Posts: 5,432	But where can I cook my bacon n eggs now ? ; )