Front brake pad rattle xj750 seca 1982

Hi all, I'm looking for some help/advice please. I have rebuilt the front calipers with new pistons,seals and pads. The brakes are great and effective. The problem comes at speeds below about 40 mph. The front pads 'rattle' (more like shake themselves apart), or bash themselves against the disk/piston. If i very gently apply the front brake, it stops. I only need to just touch the lever and it stops. So I sort of know what's happening, but not why. I believe it's only happening on the right side caliper. The noise was there before the rebuild and new pads, stopped for two days after the rebuild, then started again. The bike has just passed the UK yearly safety inspection (MOT), which tests the brakes thoroughly. All shims are in place, as are the anti rattle springs. Discs seem fine. The pins are fine and greased. The noise is so bad people duck and turn to see what is falling apart ! Thanks in advance

John

 

Closely examine the Slide Pin and other traveling parts for wear.
Likewise, ... examine the Bore in which the Slide Pin fits for out-of-round (egg shaped) wear allowing the Caliper excess movement.

The noise stops when you apply the Brake because the Pads dragging on the Rotors force the Caliper against it Travel Limit quieting the jiggle(ing) about.

 

You could remove the the anti rattle springs / plates? and re-tension them ie. bend them to put more tension on them and a dab of silicon sealer on the back of the pads. Those things worked for me.

 

Thanks for the replies. There is play in the pins, but it doesn't seem excessive, but I don't have the tools to measure them, or the holes. I have tried to source new pins with no luck yet. I will take out the anti-rattle springs and try bending them. When you say 'put a dab of silicon sealent on the pad, do you mean smear the whole of the back of the pad ? (Sorry if I'm being dense).
It just so happens that I have a set of R1 callipers that I had on my FJ1200. So mid-term I will look at getting the discs to match and look at fitting them. I have seen an adapter on the forums somewhere.

 

The 'dab' probly more like dabs.. on the cleaned edges of the piston facing the pad and similar on the other pad side, press the pads on firmly so they start off straight / flush.

 

HI I know its a little late and i hope you have solved the rattle as i have just done with my 1982 seca 750... there should be a pair of rubber boots on the slide pin..2 per calliper. Good luk

 

I think I've got this rattle. It's almost all the time, but never when I apply any pressure to the brakes. I'm looking at these dust boots (HCP9813SET2) from Len's catalog, but I'm wondering if there is an alternative. These boots are pretty expensive for something that is just really annoying - they function fine.

 

there are 2 pins in the caliper one for the pads and one that allows the caliper to slide.

are the boots needed yes they are to keep the pin clean and lubed. with out them you will be needing new pin sooner and risk road crap build up on the pin.

costly yes but slide pin and new pads add up. you may be able to find or make a bellows from something but will it work is another story

you wont need another set for many years

 

The dirt and crud that will accumulate inside the hole and will actually ream out the hole in the holder block (aluminum) much quicker than eating up the pin (steel) and then the mis-shapen hole will eventually render the mounting block un-usable..........

 

Well you may be as surprised as me, but those boots were intact and I just scrubbed them down and lubed them up and we're done rattling all over the place!