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Replacement Bolt Threads Etc


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After much failed bleeding, I have resigned myself to the fact that the caliper of my sons bike is well and truely siezed (the joys of buying from ebay but this appears to be the only real fault).

One bolt was quite rounded (the ones that hold the two halves of the caliper together) but I have managed to release it with an impact socket. This makes me think that it has not really be paid much attention from the point that it was rounded off. How the lad was riding in it in competition is beyond me! but anyway........

Once I have serviced the caliper (Im hoping otherwise its going to be a replacement one!) I am going to need to replace the bolts. Their are loads of places on line in the UK but they are asking for thread sizes. The bolts have a number of letters followed by 8.8 so I am assuming they are metric M8 bolts as follows:

material A2 grade stainless steel

thread diameter 8mm

thread pitch 1.25mm

width across flats 13mm

head height 5.5mm

Any thoughts or information to validate this ?

Rob

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Hi

Bolts on anything other than old British stuff will almost certainly be metric.

8.8 is the grade of bolt, high tensile in this case, the numbers tell you nothing about the size, you will have to measure that.

Have you not got a local "bolt shop" where you could go in with your sample? far easier than messing around on-line

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The bolts that hold the rear caliper together are a spesial that is from AJP. It can be sourced, I think, if your bike is a '02 and up with the rear caliper inside the swingarm like my '07, a glance indicates that it is a 8mm x 1.25 thread, 40mm in length, with a special 10mm washerhead hex. Appears a conventional 13mm hex has no clearance for turning.

The only alt I can think of would be a LOW head allen cap screw for clearance. Can be had, just have to find it! ;)

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The bolts that hold the rear caliper together are a spesial that is from AJP. It can be sourced, I think, if your bike is a '02 and up with the rear caliper inside the swingarm like my '07, a glance indicates that it is a 8mm x 1.25 thread, 40mm in length, with a special 10mm washerhead hex. Appears a conventional 13mm hex has no clearance for turning.

The only alt I can think of would be a LOW head allen cap screw for clearance. Can be had, just have to find it! ;)

Caliper is above the swing arm (part no R064 from the 02 series spare parts book looks identical but they only list the whole caliper not the bolts). Anchored thru the rear wheel spindle with a lug on the rear swing arm to hold position. Bolt head is a standard 10mm with plenty of space to get either a ring end or socket onto it.............did they change mid model ??

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I am guessing your son's bike is a 125. In that year I believe the 250 / 290's went with the in the swingarm style caliper and the 125/200 had the over the swingarm model still.

Are you needing the bolt that holds the caliper halves together? I believe that was what you said. Anyway, I will try and look at mine this evening but you may just ask around at a trials gathering, I think they are a custom, not standard bolt.

Edited by Alan Bechard
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Although the caliper layout did change, I doubt there is any reason that a standard 8 x 1.25 allen head capscrew of the proper length would not work on that one. All they have to do is hold the caliper together. Even my local hardware store or boat shop stocks these in stainless steel!

You agree Al? I no longer have one sitting here to look at.

Clearance is the issue on the newer ones, Clarence! There is little! ;)

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Thanks to everyone who has hunted around / given advice............

Have managed to strip the caliper and get it working (hoooooorah!). Tip from a friend was to cut down a spare brake line, connect this to a compressor and use that to push the caliper out. Worked for one side OK, but the other would not shift. Splitting the caliper and pushing the compressor nozzle direct against the o-ring shifted it!

So its all cleaned up and working. Have managed to get the caliper back together and have found a local motor factors who think they can pattern the bolt for me. Also found the bleed nipple was rounded! so another little item to replace......

thanks again to everyone for taking the time to give advice etc

Rob

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Hi Rob,

You can always use a standard allen head bolt, M8 x 1.25 (Thread pitch) 40mm long (or whatever length) then just turn down the allen head for extra clearence.

To get the pistons out next time, it's always best to pump these out first with the hydraulic pressure otherwise, you can use a small lathe 3 jaw chuck to grip the inside of the piston to draw this out.

Bye, PeterB.

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  • 2 weeks later...

Thanks once again to everyone, but I was celebrating to early..........................still not enough bite so it looks like its coming off again. Have looked at the pistons and the inner one is working but the outer is still solid???? its actually causing the caliper to flex apart as the outer stays static and the inner applies the load.......

So a few more questions.......

1) What is the size of the bleed nipple ????? soooo many sizes on the net! It is a combined banjo/nipple so I could just replace the nipple (but dont know the size/thread pitch) or should I just replace the whole banjo/nipple combination (once again is it 1 or 1.25 pitch)

2) Will have another go at cleaning the callipers but if it is shot what's the cost of a new rear calliper and where in the UK is the best place to buy (mail order preferred)

cheers again

Rob

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1) What is the size of the bleed nipple ????? soooo many sizes on the net! It is a combined banjo/nipple so I could just replace the nipple (but dont know the size/thread pitch) or should I just replace the whole banjo/nipple combination (once again is it 1 or 1.25 pitch)

Rob,

I'd replace the banjo/nipple combination and I think the standard European banjo bolt thread is 10 X 1.0

Jon

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The banjo bolt and bleeder appears to be listed in the Sherco parts manual so your local dealer of distrubutor should be able to supply them. O/h kits as well!

If you have no one, the only source I know is MRS(Rathmell Trialsports) in the UK. I hear they are very good, but you need to call, and maybe develop a relationship.

I happen to have a combo sitting here, and yes the banjo does appear to be 10x1, tho not sure about the bleeder size. Not doing you any good though!

Best I can tell you,

Cheers,

MC

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