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Hey Guys. Just spent the last hour searching but no real answers came up. Really need some help here

Bought a 1988 ZX400G about two weeks back. Totally stripped. Putting it together now. I put the calipers on and started to bleed them. Spent a good hour on the back brake and getting no pressure. Decided to move to the front brakes just to realise that the brake lever takes ages to return after I squeezed it. What can be the issue with these to problems?

Any advise would be greatly appreciated.

Chris

the only time that has happened to me was when i had air in the system, therefore it cant pressurise and you end up with nothing at the lever, and no pressure in the brakes.

remove the brake caliper and try to get the brake line nearly vertical (i.e. remove the caliper whilst its attached to the brake line, bring it up through the front of the fairing and hold it upright) and bleed again (put a bit of wood/spanner in the caliper so you dont pop a piston out).

have you fitted braided lines, and does your front brake have a splitter so that you have 1 brake line from the master cylinder to the splitter, and then it splits into 2 lines, as they are notorious for getting air in them...

banner001 wrote:the only time that has happened to me was when i had air in the system, therefore it cant pressurise and you end up with nothing at the lever, and no pressure in the brakes.

remove the brake caliper and try to get the brake line nearly vertical (i.e. remove the caliper whilst its attached to the brake line, bring it up through the front of the fairing and hold it upright) and bleed again (put a bit of wood/spanner in the caliper so you dont pop a piston out).

have you fitted braided lines, and does your front brake have a splitter so that you have 1 brake line from the master cylinder to the splitter, and then it splits into 2 lines, as they are notorious for getting air in them...

Will try that tomorrow morning. Was also thinking about reverse bleeding. Saw a nice video clip on Youtube on reverse bleeding with a seringe and a clear pipe.

Unfortunately it does not have braded lines (yet), and it does have a splitter. Would reverse bleeding work with a splitter?

Thank you kindly for the advise

Chris

ive never liked reverse bleeding, just remember that air travels against gravity, so get the calipers as high up as possible (tie them to something if possible), leave them there for an hour whilst tapping the lines and calipers to dislodge any loose bubbles, then bleed them like that.

if the lines are completely full of air it will take a while to pump fluid into the lines and into the calipers.

if you cannot get any brake fluid to come out of the calipers at all then it might be your master cylinder, also remember to bleed the caliper furthest from the master cylinder first (so thats the one attached to the splitter on its own).

the master cylinder internals will wear down eventually, remember that these bikes are pretty old now, if your master cylinder has gone, and a rebuild kit doesnt fix it, then you might need to get a new master cylinder assembly.

Thanks very much Banner. Will look into it as soon as I wake tomorrow. Luckily I have a Hyosung GT250 that is totally screwed motor wise. Maybe I will be able to make that M/C work for the time being if necessary. Parts are a problem in South Africa for these bikes though.

Well if its an option you could always use a go between. Someone to buy things in probably the US (usually the cheapest place for parts) and post it to you.

Moriman could sort you out for parts too.

Managed to sort the brakes out. Front master cyclinder was gone so I used the master cyclinder of my Hyosung GT250. Works a charm. The brake light switch barely has time to click before the brakes are at full force. Unfortunately I couldn't get the adjustable brake lever to fit the Hyosung M/C. Rear brakes just needed patience and a lot of elbow grease.

glad you got it sorted, i need to replace my front MC as well. the rebuild kit i fitted did practically nothing...

Well I can't say if its the bikes standard brakes or the Hyosung M/c but they feel strong enough to lift the back wheel if I'm not carefull.

If lines are full of air, one way is to prime them by putting the loose ends of the lines where the attach to the cslipers into the reservoir and pump the lever, keep filling up the reservoir, this will fill the lines with brake fluid then carefully take them out with a towel round them and attach to caliper, found this on hels brake doctor