Changing brake fluid

[Derek_Mac 1,404]

 How many people change their brake fluid according to the service schedule?

 I check the moisture content of mine and if the tester deems it to be at an acceptable level I just leave it without changing it.

[Guest sykospain]

I always understood from BMW ABS that riders who didn't have the MoDiTec computer facility couldn't ever try changing brake fluid in an ABS braked bike, 'cos without the machine, there'd be bubbles in the ABS pump /monitor thingie when you thought there weren't.

[Trev 18,699]

Had mine done as part of full service by local bike mechanic when NC hit two years old, didn't notice any improvement in braking feel or performance but then didn't expect too. On other bikes (non ABS)  I tend to do every 3 - 4 years but many get switched more often as I change seals, upgrade hoses, etc.

 

Made a massive difference to my Royal Enfield which I'm guessing had the same fluid from when it left the factory in 2008, I broke the level casting last Winter (dropped it on ill advised attempt at green laning!) and sourced a second hand replacement, obviously had to bleed through as disconnected the hose at the handlebar end so decided to bleed through new fluid, should have known fluid was past it's best 'cos the colour was dark urine gold 

[prr 153]

Mine is to be changed. It is not only the measurement but if it looks dark (as mine) it is time. Also it is recommended to change it every two years and that's exactly what I'm planning to do. BTW because of the break fluid or because of the single disk I ran off track as the brake lever simply touched the handlebar and I could stop ...

[beep 1,232]

It's worth noting that from a DIYers point of view the 700 with it's CBS would be much more of faff to do - I've read the manual and it's fairly complicated but doable.

 

Most car and bike manufacturers seem to recommend every two years but on the occasions I've had the fliud checked, it's always had low enough water content to suggest that 4 or 5 years would make more sense, Even at maximum recommended water content the brakes should still work fine, but it's then time to change.

Edited October 14, 2015 by beep

[Derek_Mac 1,404]

I always understood from BMW ABS that riders who didn't have the MoDiTec computer facility couldn't ever try changing brake fluid in an ABS braked bike, 'cos without the machine, there'd be bubbles in the ABS pump /monitor thingie when you thought there weren't.

 

 I think it depends if the ABS system has an accumulator in it or not.

The Service manual for the NC advises the use of a power/vacuum bleeder, but if they're not available it can be done by the traditional method.

There's no warning about the ABS system given in the service manual.

[Derek_Mac 1,404]

It's worth noting that from a DIYers point of view the 700 with it's CBS would be much more of faff to do - I've read the manual and it's fairly complicated but doable.

 

Most car and bike manufacturers seem to recommend every two years but on the occasions I've had the fliud checked, it's always had low enough water content to suggest that 4 or 5 years would make more sense, Even at maximum recommended water content the brakes should still work fine, but it's then time to change.

 

 The only real complication is the extra bleed nipple on the front caliper for the line from the rear master cylinder/delay valve, presumably when you're bleeding the rear circuit this needs to be bled before the rear caliper.

 

Edit: Typos.

Edited October 14, 2015 by Derek_Mac

[embee 7,288]

I do my own, no issues at all. My Deauville is CBS non-ABS, the Integra CBS+ABS. Neither is a problem ...................... but I use a Mityvac vacuum pump system to do it.

 

If you want to change brake fluid or just bleed brakes, I really can't recommend the vac pump system strongly enough. There are alternatives to the Mityvac, but that's a well known brand and I first came across it when working in the auto industry, our test bed area used them and they are very good quality stuff.

 

It's worth getting the brake kit, which includes a pot with hose connections and a selection of hoses etc., it just makes life easier to have all the bits. The only gripe I have with it is that the pot tends to want to fall over, and I made a heavy base for it, a steel plate with a short tube welded on which the pot sits inside. You could do a similar thing using wood etc.

 

I empty the reservoir first using the pump, no need to put all the old fluid through the system. Refill the reservoir and allow it to stand for a bit to ensure all air bubbles are out. Fit the vac pump system to the caliper bleed nipple, pumpa vacuum in the pot, and open the nipple and the fluid comes out. No need to worry about air leaks at the nipple threads since the pressure is lower in the vac hose so air cannot get back into the brake system.

 

The best aspect of this system is that the fluid is drawn though in a constant stream, so carries any air/dirt with it effectively. Make 100% sure you don't let the fluid level drop too low in the reservoir, otherwise you have to start again! Plenty of youtube vids showing it in use.

 

Some say the Mityvac is a complete overkill and you can do it "the traditional way". All I can say is if you read all the threads on bike forums about people who have trouble bleeding their brakes effectively it might sound a little different. I never have any problems with spongy brake feel, it works first time every time. These vac systems cost typically £35 - 40, money well spent, you won't regret it. I imagine there are fake (copies?) ones on auction sites, but reputable sources are plentiful, Amazon etc.

[kharli 100]

 I thought the primary reason for two yearly brake fluid changes was the fact that moisture slowly gets into the fluid via the calliper seals  . This moisture on heavy braking can effect braking performance by creating vapour from the heat produced .  I doubt in most normal riding this will be noticed at all.

  I had no trouble bleeding from the three nippled nc700x but i am interested in sykospains comment .

[Guest aknowler]

    When I done the brake fluid change on my 700 ABS, I found it very straight forward. Using the well proven method of pump/tighten nipple/allow pedal or front lever to return naturally. Repeat until clean fluid appears. The order I done it in is rear brake/middle front piston(this is actuated by rear brake pedal)front brake. Note, when doing front middle piston push brake pedal  past the first point of resistance in order to open pressure differential valve to allow clean fluid to reach the front piston.

    Remember to keep both fluid reservoirs topped up. Plenty of rag aroud fluid reservoirs to catch spillage. It took me about half an  hour taking my time.

    Hope I have explained this in an easy to understand way.

    Ride safe.

   Alan.

[Guest bonekicker]

I have heard they are advising owners to change the air in both front and back tyres at 20000 miles!!

[Trev 18,699]

I do my own, no issues at all. My Deauville is CBS non-ABS, the Integra CBS+ABS. Neither is a problem ...................... but I use a Mityvac vacuum pump system to do it.

 

If you want to change brake fluid or just bleed brakes, I really can't recommend the vac pump system strongly enough. There are alternatives to the Mityvac, but that's a well known brand and I first came across it when working in the auto industry, our test bed area used them and they are very good quality stuff.

 

It's worth getting the brake kit, which includes a pot with hose connections and a selection of hoses etc., it just makes life easier to have all the bits. The only gripe I have with it is that the pot tends to want to fall over, and I made a heavy base for it, a steel plate with a short tube welded on which the pot sits inside. You could do a similar thing using wood etc.

 

I empty the reservoir first using the pump, no need to put all the old fluid through the system. Refill the reservoir and allow it to stand for a bit to ensure all air bubbles are out. Fit the vac pump system to the caliper bleed nipple, pumpa vacuum in the pot, and open the nipple and the fluid comes out. No need to worry about air leaks at the nipple threads since the pressure is lower in the vac hose so air cannot get back into the brake system.

 

The best aspect of this system is that the fluid is drawn though in a constant stream, so carries any air/dirt with it effectively. Make 100% sure you don't let the fluid level drop too low in the reservoir, otherwise you have to start again! Plenty of youtube vids showing it in use.

 

Some say the Mityvac is a complete overkill and you can do it "the traditional way". All I can say is if you read all the threads on bike forums about people who have trouble bleeding their brakes effectively it might sound a little different. I never have any problems with spongy brake feel, it works first time every time. These vac systems cost typically £35 - 40, money well spent, you won't regret it. I imagine there are fake (copies?) ones on auction sites, but reputable sources are plentiful, Amazon etc.

 

I've a few bikes, several of them getting on a bit, so I find myself bleeding brakes quite a bit - or at least it seems like it! I have a non-return valve on a piece of plastic tube and that works ok but each time I remind myself I should invest in a vacuum kit and then forget, until next time. I'll add the Mityvac to the Christmas list, thanks for the info 

[chris 357]

I changed the fluid on mine this weekend. I use a simple brake bleed too - non return valve on the end closest to the bleed nipple. Very simple and not at all complicated - just need to top up the fluid in the reservoir before it gets too low. Took maybe 10 minutes. Swapped the rear pads as well - I changed the fronts at 17,600 and the rears were worn close to the wear indicators at 18,200km so thought I'd swap the fluid now with fairly new pads front & rear. That way the fluid level will be fine for new pads so when I next change there won't be much chance of causing fluid overflow when I next change the pads.

[reedx 48]

Just watched a couple of Youtube videos of the Mityvac - looks a great bit of kit. Which model do you have Embee?

 

Colin

[embee 7,288]

Mine is an old metal switchable pump/vac with a gauge, I don't think that exact model (Silverline Plus 04050) is made any more but there are equivalent modern versions (more or less like this http://www.amazon.co.uk/Mityvac-MITMV8500-Silverline-Vacuum-Pressure/dp/B0002SQYUA  )

If you will only use it occasionally the plastic ones are absolutely fine, and the gauge is not usually necessary (I have used it for checking pneumatic valves etc). Metal versions are a bit more robust but somewhat more expensive. 

[reedx 48]

Thanks Embee, that's really useful.

Colin

[Guest GeoffThai]

I bleed my brakes myself but use a large plastic syringe and tube as the vacuum and simply open the bleed nipple and draw the old fuid out. Slow method but you can do it all single handed and watch the level in the reservoir at the same time. No leaks as no pressure used.

[Guest sykospain]

Sounds like it's a go-er then, particularly on the 750 bikes 'cos they no longer have the linked braking system that was on the earlier 700 series.

 

When I was selling my last Beemer, I replaced the original bleed nipples back on the bike and kept the expensive Speed Bleeder one-way nipples - front and rear -  for possible use on the Honda.  Thirty snoojits a throw...On my earlier non-ABS BMW they made the old-fashioned, loosen-pump-tighten routine an absolute doddle. No constant need to wrench the opened-ring nipple spanner / key.

 

So it looks like I'll be ordering a vac-pump kit next month, Murray.

[embee 7,288]

Sorry about that.

 

I have plenty of other ideas how you can spend your hard earnt.

[michael 324]

Every 2 or 3 years I'm a "replace the brake fluid and coolant," type of fellow.

 

Although mechanically enough inclined, i'm not confidentially wanting to do it myself. More so for the added inconvenience of disposing of the used fluids.