Brake fluid change - mileage or time limited.

[MatBin 5,109]

4 years old, 10,000 miles, NC with ABS.

Brake fluid change required? Not sure if it's ever been done as I am second owner, bought at 3 years old, service book doesn't really indicate if it was done at 2 years.

I read that abs systems need a 2 yr interval as the fluid can contaminate and mess up the abs system. Car being done at kwikfit for £35 all in, local bike shop quoting could take an hour and a half at £80/hr plus fluid.

Is doing it yourself easy? I am pretty competent but did a BMW bike years ago and it all went belly up so had to take it to dealers (slowly ).

[ChrisCB 6,686]

Two years is the normal, recently changed on the CB500F and checked the old fluid with my meter and it was in the orange sector for moisture.

[Andy m 23,707]

Time based. I wouldn’t stick rigidly to 2 years but it's close, certainly before 5 years. Use will actually help, the heat gets rid of some of the water which is the main problem. 

 

Andy

[Johnnie Mototrans 2,769]

Easy peasy Matt

Brake fluid is cheap.

A short length of poly tube and a bottle or jam jar and away you go.

Unbolt the rear reservoir and pull it forward to give access.

Cover your paintwork with an old towel to protect against any drips and spills.

Just dont introduce any air.

 

 

[Xactly 5,484]

12 minutes ago, Johnnie Mototrans said:

Easy peasy Matt

Brake fluid is cheap.

A short length of poly tube and a bottle or jam jar and away you go.

Unbolt the rear reservoir and pull it forward to give access.

Cover your paintwork with an old towel to protect against any drips and spills.

Just dont introduce any air.

 

 

What he said. Time related as far as I’m concerned. Biggest issue is water contamination as brake fluid is hygroscopic.  It’s a simple enough job. I use a turkey baster to suck out most of the fluid rather than pumping it through. I’ve used a simple Halfords one-way bleeder for years (basically just a tube with a ball-bearing in one end enclosed in a plastic container). I note that Honda specify replace of brake hoses after 4 years. Eventually they collapse leaving bits of rubber that bung up holes in the system and contaminate the fluid. Most replace with braided hose, often fitted from m new on some makes. I doubt that many people would renew if there’s no sponginess in the system…

[MatBin 5,109]

I have a Sealed vacuum pump, so I will use that to get old fluid out.

Hose replacement sounds like a bit of an issue though, doubt I will bother with that unless fluid is contaminated.

Cheers all.

[rjp996 1,091]

i did mine at 3 years and was surprised at the positive difference, I was not expecting it to really be noticeable.

I got a one way valve bleeder from Halford I think , and changed by just keeping the reservoir topped up and pumping the break (making sure the reservoir never runs dry), until the fluid started coming through looking fresh and new - that way no air to bleed. Simple and very quick to do, so I would recommend.

 

[Andy m 23,707]

Two to three years seems to suit most UK conditions. You can get commercial testers which work but won't pay for themselves unless you run a fleet of vans. At the other end of the scale we have the MOD who will variously replace it in their museum fleet of Landrovers and Bedfords every 12 months for under 1 mile a year while leaving it 25 years+ in artillery pieces then want to change every valve and pipe ☹️. Quarter century old fluid properly stinks. 

 

Bleeders:

 

A jam jar works. Best to add a clothes peg to stop the pipe coming above the surface and it really is a two person job. 

A syringe works. Can be a swine to stop it popping off the end of the pipe. 

The little one way valves work. They are almost disposable and make it a one man job. 

The mitivac type hand pumps make an easy system a fast one man job and make awkward systems with ABS modulators set higher than they should be possible. Unfortunately they don't last if any fluid gets in the pump seals. At 5 years old you'll find they won't pull a vacuum, which sucks (tish-boom 😁😁😁😁😣😁) 

For really nasty systems and/or commercial speed, if you have a compressor, the bottles than convert pressure to vacuum are as good as it gets in a non-specialist workshop. 

When the vehicle manufacturer has to put diagnostic kit on and cycle the ABS pump or supply a "wet" modulator it's because they ****ed up the installation. Keying the ignition a few times may have the same effect but some are really bad and you do need the dealers kit. 

 

If a system won't bleed, fix the control in the full on position, reservoir full and leave it overnight. Bubbles rise naturally. 

 

Wear gloves and overalls. Brake fluid is nasty. 

Check the container has the right markings for DOT4/5 and is new (MOD again, ten year old hydraulic oil 😕). I know it seems a waste to buy a litre and bin 800ml, but you can't seal the bottle for 3 year. 

 

Andy

 

[Xactly 5,484]

And cover the tank with something to prevent brake fluid ruining the paintwork. I always have a spray filled with water to deal quickly with any spillage. And don’t mix DOT 5 with DOT 4 or 3.

[MatBin 5,109]

Did it yesterday, fluid in both reservoirs looked very clean, so it's possible/probable it was done either at 2 years or as part of the service they did last year before I bought the bike at 3 years old, sadly there was no documentation either way.

The Sealy pump broke half way through the operation so I had to resort to jam jar method but everything fell to hand to make it a one person job.

No noticeable affect on brakes at all, so I suppose that's a good thing (?), meaning they were fine to start with.

I think fork oil might be next.

[Johnnie Mototrans 2,769]

Way to go Matt.

And over £100 saved.

 

[Tex 36,817]

 

On 14/08/2021 at 08:14, Andy m said:

When the vehicle manufacturer has to put diagnostic kit on and cycle the ABS pump or supply a "wet" modulator it's because they ****ed up the installation. Keying the ignition a few times may have the same effect but some are really bad and you do need the dealers kit. 

 

How do you mean? The fluid in the abs unit needs to be changed, and unless the pump is cycling then the fluid will just sit there. How can that be changed by ‘installation’? Please give your answer in simple terms, like you’re explaining it to a three year old. 
 

Matt has changed the brake fluid in his brakes but not in his abs unit which can only be done with the right kit. True or false? 

[Andy m 23,707]

An ABS pump does not intervene until wheels are in deep slip. The brakes just work like there is no ABS, fluid passes straight through. With a good installation this happens when bleeding. 

 

The ABS pump however has various nooks and crannies. If the design places these above the flow it is where any air will rise to. The solutions vary:

 

1. Cycle/run the pump because the action clears them. This can be a case of keying on ten times so use the self test or going into diagnostic software to tell it to run. You can't just jump onto the battery as you don't know how long it can run for without burning out. 

2. Use a pressure bleeder to create a flow so fast that turbulence clears pockets . 

3. Dismount the pump, place it in an orientation that places the dead end in or below the flow and continue from there. 

4. Supply whole ABS units in sealed packaging that have been factory filled under pressure. These must be handled in the right way so when the packaging is removed the fluid is not replaced with air. 

 

3 & 4 are stuff-ups. 

 

Andy

 

 

[MatBin 5,109]

My view is I have replaced the fluid, or at least most of it as the abs unit has some oil in it which has not been replaced. All the videos on YT indicate a simple system as on the NC require a simple bleed procedure i.e. open caliper nipple, drain through, close nipple, repeat until fresh fluid appears, or top up reservoir a few times if existing fluid is clean and hard to distinguish between it and new fluid. Which is what I did, both front and back with no discernible difference, not sure what will happen when or if abs kicks in, I doubt I will ever know given how I ride

I think the amount of  'trapped' fluid in the abs unit is so small it can be ignored.

On my BMW K75S bleeding introduced or created an air pocket, so was a slow/careful ride to the dealers for them to fix as the brakes hardly worked at all

Edited August 16, 2021 by MatBin

[ChrisCB 6,686]

Cycling the ABS pump with diagnostic equipment is only necessary if the ABS pump is replaced, in normal service procedures you bleed conventionally without introducing any air into the system, when I replaced the brake hose on the CB500F for a longer master cylinder hose to the ABS pump (lots of air in it) I bled it normally and on road test applied the brakes as to activate the ABS, all is well in the world.

[Xactly 5,484]

That’s my approach too. On the BMW oilheads I used to own, both with ABS2 (pre-servo), I just used to pump it through in the normal way. Occasionally when I had the tank off I’d do the two bleed nipples on the ABS unit. The first time I did it there was slight discolouration but after that with regular two-yearly changes it was always clean. I had no bother with either my K100RS or K75S, both with ABS1. I may have removed the rear caliper to get the nipple to the uppermost point - can’t remember now. Certainly replacing the rear caliper mount on my Thruxton 865 with a TTP up and over mount (why do they not mount them above the swinging arm? Meriden made the same mistake with the earlier T140 models) made rear brake bleeding easy.

FWIW I try to limit the full-stroke pumping of the master cylinder, as it has been known for a leak to develop after bleeding because the seal gets damaged by a lip that forms because normally only part of the full stroke is used in operating the brake. It happened to me years ago after bleeding the front brake on my T140V. That is why I use a turkey baster to remove most of the fluid from the m/c reservoir rather than pumping through the system. It saves time too. 

[Andy m 23,707]

A picture from Twittering 

 

This used to be brake fluid. 

 

Estimated age 20+ years ☹️ At least we can't smell it 😝

 

Andy

[NickT 9]

The biggest part of the job on my 2012 NC700s was taking off enough bodywork to get to the rear master cylinder. It is worth doing as the fluid will absorb water, and so I suppose under very very (very) heavy braking this could boil and cause brake fade. 

[outrunner 4,457]

On my 2016 X you just undo the bolt that holds the master cylinder and swing it out from the frame, is the 700S not the same?

 

Andy.

[Grumpy old man 4,682]

If the rear reservoir hasn't been inspected for a while you could have problems undoing the screws that hold the top on, get a good screwdriver. 

[Andy m 23,707]

A good JIS screwdriver. 

 

Andy

[RC166 701]

And if you haven’t got a JIS screwdriver, a Phillips is much better than a posidriv.

[larryblag 14,236]

Best pronounced J. I. S 

To avoid unexpected results in your local tool shop 🤔😉

[ChrisCB 6,686]

Newer Philips have anti ramping tips that work with J.I.S.