What brake fluid and how often ?

[Nick JacksonMember]

After a few tough rides with some seriously long steep downhills my front brake started feeling a less progressive and very jerky. Aaron commented on it too at Nundle after I tried to sort out the issue with new pads, so I figured it had to be the brake fluid?? Maybe I’d boiled it on the Noosa or Lowanna rides ?

I bought some Motul 660 racing fluid to replace the old fluid, it has a higher boiling point and I was advised that it was really good stuff.

I fully drained the old fluid and bled through the Motul, I thought it wasn’t bleeding as the lever felt so light but when I spun the wheel I realized that I HAD full brake , it was just the brake was very light and with a lot of feel.

It got me wondering how often others replace their fluid and how often we should be doing it ?
Which fluid is the go ?
Was the Motul 660 overkill for just trail riding ?
Also was my fluid just old ( I’d think it was original 2008) or was it boiled at some point to get such bad brake feel ?

Nick

[Matt BakerMember]

I just use any old ‘dot 4’ stuff or whatever the manual suggests and change it once a year. Hydraulic clutch fluid once a year too if you have one. (Its not brake fluid, its a special clutch fluid)

[Steve WyethMember]

Use DOT5.1 not DOT4 for better boiling temp. resistance. Motul 660 may well be 5.1 for all I know just saying to use 5.1 if you haven’t already.

I hardly ever bleed my brakes, if they start to feel spongy then I’ll do it otherwise they seem to be fine. To do it properly though you really need to take the brake off completely as the banjo fitting at the master cylinder on the bars has a high point (it does on KTM/Bergs anyway) and can leave a bit of air in causing spongyness. Not forgetting the il is hydroscopic and will build up water over a period of time.

There was a good thread on here about brake bleeding, the serach function is rubbish though so I couldn;t be bothered to look through a million posts for you. Maybe you can ask a moderator to help you out or fix it?

[Nick JacksonMember]

moto wrote:

Use DOT5.1 not DOT4 for better boiling temp. resistance. Motul 660 may well be 5.1 for all I know just saying to use 5.1 if you haven’t already.

I hardly ever bleed my brakes, if they start to feel spongy then I’ll do it otherwise they seem to be fine. To do it properly though you really need to take the brake off completely as the banjo fitting at the master cylinder on the bars has a high point (it does on KTM/Bergs anyway) and can leave a bit of air in causing spongyness. Not forgetting the il is hydroscopic and will build up water over a period of time.

There was a good thread on here about brake bleeding, the serach function is rubbish though so I couldn;t be bothered to look through a million posts for you. Maybe you can ask a moderator to help you out or fix it?

can’t find it either !!

Do you only bleed the brakes if they feel spongy or completely replace the fluid ?

Nick

[Geoff ForshawMember]

AP Racing PRF 660. This is a high temp racing brake fluid that is compatible with all Dot 4 or 5.1 systems. It is not silicone based. DO NOT USE Dot 5.0 as it is silicone based and will destroy your seals and lead to brake failure.

Lefty

[GregMember]

I reckon you should do it every 6 months or like LC at least every 12 months. As the fluid absorbs moisture from the atmosphere it goes off. It does over a long period a little at a time and you dont notice until you replace the fluid and get the wow factor like you Nick. You dont realise how bad there are cause you got used to it over time as it went off but new fluid properly bleed :woohoo:

I reckon DOT 4 will suit most of us DOT 5.1 if you are faster or harder on your brakes. I am a rear brake dragger. Be aware fluid goes off in the bottle so I reckon if its a year or older maybe think of getting a new bottle. I have run the Motul for years Nick (I like Motul products but thats just me) I have recently been put onto a fluid by Lefty that by all accounts is the ducks guts. I had boiled the fluid twice on the rear of the Tenere, Lefty got me onto the new stuff and I havent boiled it again. (the backing plates on the pads now go a very dark blue :blink: )

To answer your question regarding the fluid boiling and feeling different did you notice a difference in the rear brake on your Tenere when you boiled in on Yengo that evening we rode through?

Just found the video

http://www.youtube.com/watch?v=HnUz-cuD5Eo

Hope some of that helps :blink:

TB

[Geoff ForshawMember]

LC4skin wrote:

I just use any old ‘dot 4’ stuff or whatever the manual suggests and change it once a year. Hydraulic clutch fluid once a year too if you have one. (Its not brake fluid, its a special clutch fluid)

Some bikes use a mineral oil type clutch fliud and some don’t. Check your owners manual or it will be written oon the resevior. If I remember correctly Dejay had this issue last year at Micks. He bought a new clutch master cylinder and was told it had to use mineral hydraulic oil. :ohmy: This was not correct and it was meant to use brake fluid. It ruined the seals, wouldn’t bleed and he had no clutch for the weekend, luckily he had a rekluse. :huh:

If only we had looked at the resevior cap before we started to bleed it. :whistle: :blush: It stated “brake fluid”

A dozen beers before we started to bleed it didn’t help!!!!!!! :blink: :blush: :sick:

Cheers,
Left

[GregMember]

Lefty wrote:

LC4skin wrote:

I just use any old ‘dot 4’ stuff or whatever the manual suggests and change it once a year. Hydraulic clutch fluid once a year too if you have one. (Its not brake fluid, its a special clutch fluid)

Some bikes use a mineral oil type clutch fliud and some don’t. Check your owners manual or it will be written oon the resevior. If I remember correctly Dejay had this issue last year at Micks. He bought a new clutch master cylinder and was told it had to use mineral hydraulic oil. :ohmy: This was not correct and it was meant to use brake fluid. It ruined the seals, wouldn’t bleed and he had no clutch for the weekend, luckily he had a rekluse. :huh:

If only we had looked at the resevior cap before we started to bleed it. :whistle: :blush: It stated “brake fluid”

A dozen beers before we started to bleed it didn’t help!!!!!!! :blink: :blush: :sick:

Cheers,
Left

Yeah thats right Lefty, he had to rekit both again as the slave cylinder failed cause of swollen rubbers as well :unsure: Like you said it was on the cap but we all but faith in Scotty at Sutto’s. Sutto’s provided the kits and correct fluid free of charge

TB

[Nick JacksonMember]

Trailboss wrote:

I reckon you should do it every 6 months or like LC at least every 12 months. As the fluid absorbs moisture from the atmosphere it goes off. It does over a long period a little at a time and you dont notice until you replace the fluid and get the wow factor like you Nick. You dont realise how bad there are cause you got used to it over time as it went off but new fluid properly bleed :woohoo:

I reckon DOT 4 will suit most of us. Be aware fluid goes off in the bottle so I reckon if its a year or older maybe think of getting a new bottle. I have run the Motul for years Nick (I like Motul products but thats just me) I have recently been put onto a fluid by Lefty that by all accounts is the ducks guts. I had boiled the fluid twice on the rear of the Tenere, Lefty got me onto the new stuff and I havent boiled it again. (the backing plates on the pads now go a very dark blue :blink: )

To answer your question regarding the fluid boiling and feeling different did you notice a difference in the rear brake on your Tenere when you boiled in on Yengo that evening we rode through?

Just found the video

http://www.youtube.com/watch?v=HnUz-cuD5Eo

Hope some of that helps :blink:

TB

It all helps thanks TB

That vid bought back memories and I did replace the fluid straight away after that ride as the rear brake never felt the same :pinch:

Nick

[SteveMember]

But dont forget the brake line itself .it is under extream preasure to deliver stoping power to your disc.Brake lines should be replaced to,braided dont swell as much as stock.
Toes

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