Ducati Sporting Club UK
 
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-Apr-2012, 04:00
ballbag racer ballbag racer is offline
Registered Forum User
Bikes: Road, 1098s Track, R6
 
Posts: 13
Join Date: Jan 2010
Mood: mainly grey :-(
5.1 fluid

I'm just putting my rear brake back together and just wanted to know if using 5.1 fluid was ok to use? I have read a couple of articles about brake fluids and it would seem ok? Just wondered what you guys thought about it??

Cheers
Quote+Reply
  #2  
Old 08-Apr-2012, 09:35
PDL's Avatar
PDL PDL is offline
Registered Forum User
500SD
Bikes: 803 rs race bike
 
Posts: 592
Join Date: Jul 2004
No do not usr 5.1. Use Castrol SRF
Quote+Reply
  #3  
Old 08-Apr-2012, 11:09
Ghost's Avatar
DSC Member Ghost Ghost is offline
DSC Club Member
Big Twin
Bikes: Ducati 749, Phil Read Replica, DD 620
 
Posts: 1,830
Join Date: Mar 2008
Mood: 2011 DD Class 'B' Champion
Quote:
Originally Posted by PDL
No do not usr 5.1. Use Castrol SRF

Why? DOT 5 is the silicone based fluid that should not be used.

DOT 5.1 has twice the boiling point properties of DOT 4 and is fully compatible.
I've been using it on my bike since I started in DD in 2008.

Castrol SRF is great for race cars where the fluid can reach extraordinary temperatures, but on our little bikes to be honest DOT 4 is satisfactory too.
Quote+Reply
  #4  
Old 08-Apr-2012, 11:42
PDL's Avatar
PDL PDL is offline
Registered Forum User
500SD
Bikes: 803 rs race bike
 
Posts: 592
Join Date: Jul 2004
Quote:
Originally Posted by Ghost
Why? DOT 5 is the silicone based fluid that should not be used.

DOT 5.1 has twice the boiling point properties of DOT 4 and is fully compatible.
I've been using it on my bike since I started in DD in 2008.

Castrol SRF is great for race cars where the fluid can reach extraordinary temperatures, but on our little bikes to be honest DOT 4 is satisfactory too.

SRF is dot 4 as for dot 5.1 you'll be changing more often but if you've got the money then go fr it.
Quote+Reply
  #5  
Old 08-Apr-2012, 11:56
Ghost's Avatar
DSC Member Ghost Ghost is offline
DSC Club Member
Big Twin
Bikes: Ducati 749, Phil Read Replica, DD 620
 
Posts: 1,830
Join Date: Mar 2008
Mood: 2011 DD Class 'B' Champion
Quote:
Originally Posted by PDL
SRF is dot 4 as for dot 5.1 you'll be changing more often but if you've got the money then go fr it.

I know it is twice the price of DOT 4 but SRF isn't cheap either. I only as a matter of course change the fluid mid season, so twice a year, 250ml is hardly going to break the bank.
Quote+Reply
  #6  
Old 08-Apr-2012, 12:25
bradders's Avatar
bradders bradders is offline
Registered Forum User
MotoGP God
Bikes: 848, M620 DD bike
 
Posts: 11,913
Join Date: Aug 2003
Mood: waiting...
Use 5.1 and change once a year if it's lucky. Maybe it's because I don't use the brakes
Quote+Reply
  #7  
Old 08-Apr-2012, 18:49
PDL's Avatar
PDL PDL is offline
Registered Forum User
500SD
Bikes: 803 rs race bike
 
Posts: 592
Join Date: Jul 2004
Quote:
Originally Posted by Ghost
I know it is twice the price of DOT 4 but SRF isn't cheap either. I only as a matter of course change the fluid mid season, so twice a year, 250ml is hardly going to break the bank.
You're right. I like SRF which isn't cheap either
Quote+Reply
  #8  
Old 08-Apr-2012, 20:30
Shazaam!'s Avatar
DSC Member Shazaam! Shazaam! is offline
DSC Club Member
Big Twin
 
Posts: 1,167
Join Date: Nov 2001
DOT 5.1 Brake Fluid

The DOT specification for DOT 5.1 brake fluid has a higher minimum dry boiling point/minimum wet boiling point (527°F/347°F) than the DOT 4 spec (446°F/311°F), but these are just minimum specs.

Several DOT 4 fluids exceed DOT 5.1 specs. For example, expensive Castrol SRF (590°F/518°F) is used by Formula One teams, ATE Type 200 and Super Blue Racing (536°F/392°F), and Motul RBF 600 (593°F/421°F). Golden Spectro Supreme DOT 4 (520°F/367°F) comes close.

So DOT 5.1 fluid is not necessarily better, particularly after absorbing moisture. Most of us don't change our brake fluid very often so wet boiling point numbers are more important. On the track, brake fade is the main concern so we change the fluid more often and use a higher dry boiling point fluid. Generally, the higher the dry boiling point, the faster the fluid absorbs moisture from the air, Castrol SRF and the ATE fluids excepted.

If you don't change your brake fluid once a year or so, the absorbed moisture in the fluid corrodes expensive brake bits. So, do it this spring.

Castrol SRF is the best, hard to find, four-times more expensive than the others, and used by every Formula 1 team in existence because it’s boiling point drops very little as it absorbs moisture. (590°F/518°F)

Motul RBF 600 is next best and reasonably priced. Same dry boiling point and the next-highest wet boiling point. It tends to absorb water more quickly than the others so it seems to be best suited for racing applications where the fluid is changed very frequently. Keep in mind that any fresh dry fluid will be better than wet Motul because it will have a higher temperature boiling point. (593°F/421°F)

This suggests to me that ATE is the best all-round brake fluid.

BMW recommends ATE brake fluid for their street cars because it, like Castrol LMA (446°F/311°F), absorbs moisture very slowly. The advantage over LMA is that ATE has a much better wet boiling point. You can use this in your street bike and forget about it for a year or so. An excellent choice for a weekend track bike which also sees regular street duty.

ATE Super Blue and ATE Type 200 and are the same fluid. The theory is to alternate them and you can tell from the color when you have flushed all the old fluid out. In practice however, once a can is opened it should be used-up quickly. It’s not a good idea to save fluid from an opened can for color change reasons. (536°F/392°F)

As a point of reference, Motul 5.1 is 518°F/365°F.
Quote+Reply
  #9  
Old 08-Apr-2012, 23:13
banger san's Avatar
banger san banger san is offline
Registered Forum User
Mille
Bikes: DD class B, Street Triple, Tiger 1050
 
Posts: 244
Join Date: Oct 2011
Go you know if there are any compatibility issues in swapping from DOT 4 to 5 or visa versa?
Quote+Reply
  #10  
Old 09-Apr-2012, 01:13
Shazaam!'s Avatar
DSC Member Shazaam! Shazaam! is offline
DSC Club Member
Big Twin
 
Posts: 1,167
Join Date: Nov 2001
DOT 4 fluid can be replaced by DOT 5.1 fluid and vice versa.

DOT 5 fluid is different. It is silicone-based and cannot be used in Ducatis that use Brembo brake and clutch master and slave cylinders. It will damage the natural rubber seals. It is dyed purple to give a visual warning against accidental use.
Quote+Reply
Reply
  
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes
Postbit Selector
Switch to Vertical postbit Use Vertical Postbit

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Recent Posts - Contact Us - DSC Home - Archive - Top
Powered by vBulletin 3.5.4 - Copyright © 2000 - 2024, Jelsoft Enterprises Ltd. - © Ducati Sporting Club UK - All times are GMT +1. The time now is 16:43.