Brake fluid, coolant

[Derivative]

On buying the CB500 I changed the engine oil. Engines are expensive and oil is pretty mission critical. It's also very easy to do.

I've done 3k miles on it without issue.

Should I drain and replace the coolant and brake fluid? Or should I just top up as necessary?

Haynes states that coolant should be done every three years, and brake fluid every 18 months.

Changing the coolant requires removing the fuel tank. Replacing brake fluid seems like it'd best be done with a complete brake overhaul. Neither of which are particularly simple tasks.

I would trust the manual, but it also recommends changing hoses every three years, which I suspect few people actually do.

What say BCF?

[TaiChi]

The best bit of advice you'll ever hear is "if it ain't broke, don't fix it".

So many bikes are devalued by ham fisted beginners first foray into the tool box to "see how it works".

But you're talking routine maintenance, which is always a good thing if it's done routinely & if it's done well.

Changing the oil is pointless unless you change the filter at the same time, can we assume you've done this?

Coolant is also your anti-freeze & coming up to winter is a good time to be thinking about it. If I'd replaced the coolant myself in previous years, had no leaks & no need to top up, then I'd happily take it through the winter.

If not, it's an easy job to drain & refill with fresh.

With oil & coolant, DO NOT use any kind of flushing fluid or procedure unless what comes out 'alarms' you in it's condition. I feel this advice might cause a stir amongst some on here so I'll leave the reasons why to be debated.

Brake fluid is highly hygroscopic & it's performance does deteriorate with age. It's an easy job to drain & replace if you follow the manuals method of bleeding the brakes. 99.99% of the difficulties some people experience when bleeding brakes is 'cos they're unable to follow a set procedure.

A complete brake overhaul is OTT IMO as part of routine mantenance. Remember, "if it ain't broke, don't fix it", but coming up to winter, I'd at least whip the pads out, regrease the seals & rough the pads surface a little.

The calipers will suffer during the winter & a little bit of 'winterising' will go a long way to improve their condition next April, when it really would be a good idea to have a thorough strip, clean & inspection.

[.Chris.]

I'd always replace fluids like that straight away if I'd bought a secondhand bike without knowing when they were last done.

Brake fluid absorbs water over time, so will start to cause corrosion if it's just left. Although probably academic unless the fluid is really old, as it absorbs more water the boiling point will decrease, eventually reducing the effectiveness of the brakes when they're used hard.

Anti-freeze gradually loses its effectiveness in both stopping the water from freezing and stopping internal corrosion. I was always under the impression it should be changed every 2 years, and that's what I've done with my car.

Neither of these things are expensive, so personally I'd just do them for peace of mind.
____________________
Chris
1985 Kawasaki Z550F

[stinkwheel]

Both simple jobs.

The coolant is as simple as undoing the drain screw and radiator cap, allowing it to drain, replacing the drain screw and filling it up again. A short run of the engine to remove any airlocks and top it up again.

Replacing brake fluid is simple too (providing the nipple isn't seized). The trickiest bit is removing the master cylinder lid without burring the heads off the screws.

Simply remove the lid off the master cylinder, fit a bit of plastic tubing to the end of the bleed nipple with the other end in a jar and crack open the nipple. Brake fluid will start to slowly run out. When the level in the master cylinder is nearly at the bottom, top it up with fresh brake fluid from a sealed container. Repeat this process until you see the fresh fluid coming out through the tube at the bottom (the old fluid will be a darker colour), nip up the nipple, top the reservoir off to the correct level and replace the lid.

Don't let the hole in the bottom of the master cylinder become uncovered or you'll let air into the system that needs bleeding out again.

As a final touch, tie the lever all the way down to the bars for a couple of hours then slowly release it to remove any tiny air bubbles that might have gone in.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[TaiChi]

[Kickstart]

[Bloggsy]

I know it's probably over the top but I replace oil filter coolant and brake fluid once a year.the coolant and brake fluid I borrow from work so it's a cheap deal

[Derivative]

Okay, I have free time now to sort all of this out and the front pads need replacing anyway.

Coolant, it looks like I need three or four litres.
How much brake fluid do I need for a full flush? I can't really find any info on this specific to the CB. Would a litre do?

[_Iain_]

I used about 1/4 of a bottle of fluid for the GS if that
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[Derivative]

[TaiChi]

[Derivative]

Useful advice. Thanks. I have a Haynes manual, picked up for £6.

Bought pretty much everything from eBay. Not sure why I hadn't thought of that before.

500g tin of copper grease for £5.
18g tin of red rubber grease for £2.
Etcetera.

Likely going to get the coolant locally though, shipping costs make it a bit daft.

Is my shoe size relevant somehow? I'm a 9

[Derivative]

[TaiChi]

[Vincent]

[Derivative]

Done the front brake now, at least I think so. Cleaned out a lot of the crud in there - I could do more, but I'll wait until I don't need to use the bike for a while in case I knacker something up.

How firm should the lever be? I bled the system until I couldn't see any bubbles, and then a little bit more. It has a bit of freeplay, a small (<1cm) section of action and then is firm. Does that sound about right?

Rear brake is non functional because it chucked it down before I had time to finish it, had to screw everything up and stop. Quite funny to have a lever that's completely pointless.

Is it worth leaving the lever tied back overnight with the diaphragm removed? Is there an equivalent for the rear brake pedal (hanging a weight from it, perhaps?)

[Kickstart]

Hi

Where is the 1cm of play? Which end of the lever.

Don't leave the cap / diaphragm off. Won't do any good but will allow moisture from the air to contaminate the fluid. The diaphragm is there to allow the air to take up the space vacated by the fluid being used without the air coming into contact with the fluid.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[TaiChi]

[Kickstart]

Hi

Aye, by 1cm by your index finger would be a pretty large amount, while on most bikes at the far end of the lever it would be a pretty minimal amount.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[GREENI3]

If you're replacing the brake fluid anyway, get yourself some braided lines.

It makes a massive difference.

[Derivative]