SRX brakes

[Julian217]

Hi, I have a later twin shock srx 400 with a single front disc brake. Despite numerous attempts at rebuilding the front rubs slightly, and the back squeaks loudly. So I'm thinking of changing the calipers pistons etc.  There seem to be many Yamaha's that have what to my untrained eye look like the same brakes.  Does anyone know for sure which models if any have the same?

[Steve Lake]

as far as I'm aware the rear caliper on all the srx's is the same....but the single front caliper is probably only the same as other srx single sided brake systems. SteveH will know.....

Have you considered getting new seals and overhauling the existing calipers...I did this, to great effect, having had exactly the same problem as you.

You should also check that tilt plates (or whatever they are called) that sit behind the pads, are in good condition (and actually installed, often left out, or corroded away) these help to stop squeak and also tend to make braking a bit more progressive.

finally, if you havn't, fit braided hoses, vastly improve all aspects of the srx braking system.....the standard pipes expand a bit under pressure, when the brakes are released, there is a slight residual pressure that can stop the pads being thrown off the disk.

[Julian217]

Thanks, I 've no idea what tilt plates are, I definately don't have any - the pistons just work on the pads. I 'll check it out.

[Steve Lake]

in the service manual they are called a 'shim', one behind each pad.... fitted so that the trailing edge of the pad will contact the disc first (in theory),  they are not shown as being used on the rear pads, and my parts manual doesn't show any for the rear either....unfortunately i seem to have lost the page in the parts manual which covers the front brake.

[Steve H]

When you say single disc, is this the later caliper with 4 pistons. Looking at the parts list the part number starts with 2NX, which is the same as the model number, and so suggests the caliper is model specific.
The pistons and seals are 1NL-W0057-00 (pistons) and 1NL-W0047-00 (seals) The tilt pads are only fitted to the twin piston calipers.

[Julian217]

Yes its the 4 piston type.  So no shims then. At some point I'll get round to stripping it down properly, need to have a look at the head bearings too.   

[Martin Giddings]

I have an 85 SRX6 and I have an RD350LC rear brake, due to hours of comparing Yam brake dimensions at a breakers, after I knackererd the original (seized bleed valve broke the alloy around it when I forced it). The RD is better then the original (they are a little quicker).



 

[OMEGAMAN]

 
Hi, I'm building a track? srx400 for my son at the moment & have fitted it with a caliper from a TZR250 (fitted straight on with no altering!)

You will also find that calipers from FJ1100/1200 fit as well (I've used them)

Quite a few other models use the same items (but don't ask which?)  100mm between hole centres!

As for the squealing, check that the disc runs dead centre between the hard cases of the calipers & is not fouling the caliper (spacers?)

If ok then take out the pads & carefully file the leading edge of the soft pads (not the metal) to approx 45 degrees (only slightly, by 1mm or so)

Also, if you only lightly use your brakes, they will glaze over (& probably squeal?), so provide your brakes are working OK, give them a little heavy use from time to time (roughs them up & prevents glazing)

I think the rear caliper from a FZR1000 is similar to the rear srx one?

[guest288]

I know one tip is to smear copper slip on the rear of the pads before you fit them- its supposed to cut down the vibration which causes the squeaking...

[guest27]

"Apparently" - I have never done this but apparently... Dont just bolt the caliper on, bolt it loosely to the mounte and then get some one to hold it on hard, measure the gaps around the mounts and shim so the caliper is actually mounted concentric tot he disk - may need to do this with just the pistons or brand new pads.  "Apparently" - it can make all the difference to how well the brake works - means the pistons act perpendicular to the disk not at an angle, and with mass manufactured parts there can be a slight out of parallel element to the fork leg and the disk.

Have also been told that getting the caliper dead centre on the disk - thus more shimming of the mounts - make a difference.  Not sure how much, but I am told that the shimming perpendicular can make a real big difference.

All the apparently's come from a bloke I used to know who was bloody fast around the IoM course, but there again these racers wear lucky underpants.

R