Brake fluid color?

[Bob2]

Hi guys.
Changed my fluids spring of 2015. All went well with a lot of help from this forum.
My clutch fluid is now a nice tan color as expected.
My brake fluid is now crystal clear, had to remove cover to make sure there was some in the res. Is there something not quite right? The brakes are a little draggy but nothing to write home about. This is all part of my quest to find out why my front wheel is not spinning freely.
I'm sorry I don't contribute much but I definitely have been helped by many who have contributed.
Thanx in advance for your suggestions.
Bob

 

[dwalby]

My brake fluid is now crystal clear, had to remove cover to make sure there was some in the res. Is there something not quite right?

I noticed many years ago when I started using braided stainless steel brake lines that the fluid stayed clean looking indefinitely. I think its most likely because the teflon lining that the fluid contacts inside the lines doesn't interact with the fluid the way the rubber hoses do. Pure guess, I could be wrong.

 

[TerryS]

Bob the Second, I can't help with your brake fluid colour, but clear pale amber is normal for a DOT4 fluid, and it usually goes progressively darker as it ages/absorbs contaminants and water.

If your brakes are a bit draggy, the first thing I'd check is that the brake pistons can move freely (after you clean around the exposed part, they should slide back into the caliper with sustained firm pressure) and that the sliding caliper mounts are also able to slide freely. The sliding mounts should be cleaned and greased occasionally, and any torn rubber boots should be replaced.

My detailed experience is with my VFR800 with similar brakes, and I have heard that the CBS system can produce drag if crud accumulates in the proportionating valve from the rear brake. If that happens the centre pistons may be unable to relax after application.

 

[Reginald]

If your brakes are a bit draggy, the first thing I'd check is that the brake pistons can move freely (after you clean around the exposed part, they should slide back into the caliper with sustained firm pressure) and that the sliding caliper mounts are also able to slide freely.

Be careful pressing in the pistons. If you have a marginal SMC, this can actually cause it to fail; personal experience. Use the bleed nipples while pressing in the pistons, it won't put back pressure on the SMC and won't push anything back up the lines. It helps to have a one way bleed valve.

Also, make sure your caliper slide pins are clean and lubed with brake grease.

Every time I change a tire I clean the calipers and re-grease the slide pins. Takes about 15 minutes per caliper after you've done it the first time.

 

[kendoo]

Mine is usually the same color I like my beer. Right or wrong it reminds me what is waiting for me after the ride.

 

[dduelin]

Be careful pressing in the pistons. If you have a marginal SMC, this can actually cause it to fail; personal experience. Use the bleed nipples while pressing in the pistons, it won't put back pressure on the SMC and won't push anything back up the lines. It helps to have a one way bleed valve........

Brakes are critical, there is no allowance for marginal parts. A marginal SMC should be repaired before riding it, but the question raised is how would one know it was marginal prior to failing? A kick to the rear wheel during preflight to ascertain drag, frequent pad checks, etc?

How can pressing in the caliper pistons cause it to fail? Did it fail during the brake service so the actions beforehand were causal and not coincidental?

 

[Reginald]

Brakes are critical, there is no allowance for marginal parts. A marginal SMC should be repaired before riding it, but the question raised is how would one know it was marginal prior to failing? A kick to the rear wheel during preflight to ascertain drag, frequent pad checks, etc?

How can pressing in the caliper pistons cause it to fail? Did it fail during the brake service so the actions beforehand were causal and not coincidental?

In order of occurrence. All started because shop wasn't performing services correctly as I paid for them. I now maintain my brakes and they work well now. I've received a lot of assistance on this forum. If you think kicking your tires help, go for it. I check mine by temp on rotors, tire spin, and brake power. I flush the system yearly.

1) https://www.st-owners.com/forums/showthread.php?136107-Front-Wheel-Brake-Dragging&highlight=
Result - SMC created crud in it. Thought it was good after everything was working again.

2) https://www.st-owners.com/forums/showthread.php?136177-Ever-Seen-A-Pivot-Bearing-Do-This&highlight=
Result left pivot bearing in as is and keep it packed with grease.

3) https://www.st-owners.com/forums/showthread.php?147959-Looks-Like-SMC-Failed-Again&highlight=
Note John's write up about pushing crud back into SMC
Result great brakes.

 

[dduelin]

In order of occurrence. All started because shop wasn't performing services correctly as I paid for them. I now maintain my brakes and they work well now. I've received a lot of assistance on this forum. If you think kicking your tires help, go for it. I check mine by temp on rotors, tire spin, and brake power. I flush the system yearly.

1) https://www.st-owners.com/forums/showthread.php?136107-Front-Wheel-Brake-Dragging&highlight=
Result - SMC created crud in it. Thought it was good after everything was working again.

2) https://www.st-owners.com/forums/showthread.php?136177-Ever-Seen-A-Pivot-Bearing-Do-This&highlight=
Result left pivot bearing in as is and keep it packed with grease.

3) https://www.st-owners.com/forums/showthread.php?147959-Looks-Like-SMC-Failed-Again&highlight=
Note John's write up about pushing crud back into SMC
Result great brakes.

I am fortunate my dad was a mechanic and I learned from a master and since maintained my vehicles or at least am familiar with my vehicles for 45 years. I'm sure it has saved me lots of grief as well as money while giving me some working knowledge of systems.

But I did ask a legitimate question. I am sorry if seemed like a question of your ability. How does one know the SMC is marginal? You do it the same way I do from your own posts. If it's found to be sticking it's no longer marginal and to my lights never was - brakes are a pass/fail item and by close observation and regular inspections between regular services it will pass until it doesn't.

 

[Reginald]

I am fortunate my dad was a mechanic and I learned from a master and since maintained my vehicles or at least am familiar with my vehicles for 45 years. I'm sure it has saved me lots of grief as well as money while giving me some working knowledge of systems.

But I did ask a legitimate question. I am sorry if seemed like a question of your ability. How does one know the SMC is marginal? You do it the same way I do from your own posts. If it's found to be sticking it's no longer marginal and to my lights never was - brakes are a pass/fail item and by close observation and regular inspections between regular services it will pass until it doesn't.

I am a mediocre mechanic and seem to learn everything the hard way. When I did the first and second fix to the SMC it worked fine, but there had been a bunch of crud in it. Not knowing any better I went with it, now I'd just replace it. Anyway, from other's (they posted on 3) I've learned the return from the SMC can retain crud hidden in an inaccessible recess and back pressure can force it to lock up. Although it was working and took me from one coast to the other it still was just a step away from failure, making it marginal. When I replaced the rear brake pads last year I pressed them in using the brake reservoirs to handle the returning fluid like I've done with other MC brakes. The SMC failed as a result. From now on I'm going to use the bleed nipples to receive the fluid from pressing in the pistons, another lesson learned. So, the SMC can be marginal, because the SMC can work while on the brink of failure! The ST linked brake system is a PITA.

 

[TerryS]

I am a mediocre mechanic and seem to learn everything the hard way. When I did the first and second fix to the SMC it worked fine, but there had been a bunch of crud in it. Not knowing any better I went with it, now I'd just replace it. Anyway, from other's (they posted on 3) I've learned the return from the SMC can retain crud hidden in an inaccessible recess and back pressure can force it to lock up. Although it was working and took me from one coast to the other it still was just a step away from failure, making it marginal. When I replaced the rear brake pads last year I pressed them in using the brake reservoirs to handle the returning fluid like I've done with other MC brakes. The SMC failed as a result. From now on I'm going to use the bleed nipples to receive the fluid from pressing in the pistons, another lesson learned. So, the SMC can be marginal, because the SMC can work while on the brink of failure! The ST linked brake system is a PITA.

Thanks Reginald, I learnt something new there. Having the SMC clog up and then keep pressure on the back brake is a reasonably common failing on VFR800's, some have even reported the brake locking fully on, requiring the bleed nipple to be cracked to release the pressure.

It is logical that debris in brake fluid would work its way to the lowest point in the system ie the caliper, and pushing that back up the line by moving the pistons does sound like a bad idea.

 

[dwalby]

Just curious, how much "crud" are we talking about, and given that the brake fluid is a closed system, where is it coming from? Is it internal hose deterioration?

 

[Gus1300]

Just don't let it get this bad! Prior to my first full cleaning/bleed...haven't had any color in either brake nor clutch since, but it's prob time to do it again.

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