4rt Caliper Bolt Size

[cadman]

Before I get the drill out to remove them I'd like to get some replacements in hand

So can anyone tell me the diameter, length & threadpitch of the Front caliper bolts on an 06 4RT

And what material should I get the new bolts in? I know titanium is good, but would something else suffice?

And as a hint, if I drill the head off will I get the shaft of the bolts out with some vice grips, or am I going to need some heat for the lock tight, or am I going to have to also drill & retap the holes?

So if you have managed to get yours replaced, can you describe the degree of difficulty.

Thanks in advance

[rapid roy]

Before I get the drill out to remove them I'd like to get some replacements in hand

So can anyone tell me the diameter, length & threadpitch of the Front caliper bolts on an 06 4RT

And what material should I get the new bolts in? I know titanium is good, but would something else suffice?

And as a hint, if I drill the head off will I get the shaft of the bolts out with some vice grips, or am I going to need some heat for the lock tight, or am I going to have to also drill & retap the holes?

So if you have managed to get yours replaced, can you describe the degree of difficulty.

Thanks in advance

i replaced 4rt / sherco with montesa 315 bolts great quality

try sandifords

[hughesy]

I drilled mine and used an easy out ( trade name ez out, various makes available) to extract the bolts, I then replaced them with titanium bolts. I can't remember the length but pretty sure they're 8mm x 1.25 pitch.

You sometimes see them on ebay although they're more expensive than they were or try here

http://www.tastynuts.com/site/frames/frameset_shoponline.htm

Take time to make sure you drill straight and in the centre of the bolt, this bit is critical. It's a shame the originals are made from cheese!

[jimmyl]

Presume you have tried tapping the head of the screw round with a centre punch, might save drilling. If you have to drill the head off, if you take front wheel out the caliper will probably come off the fork leg leaving the stem of the bolt sticking out minus the head which can easily be clamped with mole grips. If using non 315 bolts check length of new bolts carefully as there seems to be very little clearancve behind the caliper and the heads of the bolts that hold on the disc.

[fantic156]

Hacksaw a slot, apply some heat (need to be careful direct heat may damage the lacquer) and use an impact driver before you resort to drilling. Managed to get mine out without major surgery but it was close and they where very tight to remove for quite some time after they initial give. Bought some titanium ones of ebay to replace the originals description below:-

"You are bidding on a set of TITANIUM BOLTS used to secure the front disc brake caliper of the Montesa 4RT / 315R to the front fork leg. They will fit other modern trials bikes with no problem. The package consists of following:- M8 x 60 Ti tapered Socket Head Screw, M8 x 35 Ti Socket Head Screw and a M8 Ti Form A flat washer. These all replace the soft rubbish quality standard fitment and MUST be used in conjunction with the FIM standard plastic Disc Guard shouldered washers. If you dont use the guard then these bolts WILL need to be shortened. Use the washer with the short bolt to help secure the plastic cover. Will fit other machines but may need to be shortened, please check clearance inside caliper before you ride. Thanks for looking and thank you for your business. FF "

Good Luck

[fantic303]

The bolts are 32 and 55 mm long (just measured the original ones) and yes it is M8 x 1.25.

I have made a groove in the head with an hacksaw so that I could loosen the bolt with a large screw driver. Don't use a hammer because the lug on the frontleg could break !!

Picture caliper bolts

Edited January 26, 2007 by fantic303

[gii]

The bolt heads are pathetically soft, if you've rounded out the hex, try tapping a 'torx' key into them just slightly larger than the original hex. Often works, the key grips and the tapping reduces the grip of the loctite

[cadman]

The bolts are 32 and 55 mm long (just measured the original ones) and yes it is M8 x 1.25.

I have made a groove in the head with an hacksaw so that I could loosen the bolt with a large screw driver. Don't use a hammer because the lug on the frontleg could break !!

Many thanks to all. Finally got them undone. & 55 & 32 x M8 x 1.25 is what I have also.

Off to find something that size not made of cheese :-)

Thanks again

[rhaines]

Easiest way to get them out is to cut a slot in the top of the bolt then put an impact driver on it and give it a swift whack to release the loctite.

[sr34]

the only option for me was to drill the heads off and put what was left of the bolt still in the caliper into the vice much sweet & pain later bolt came out but i did notice it was covered in red permanent thread lock i went sandifords for the 315 replacement bolt spoke to the guys there they to have the same problems they have now gone back to normal bolts from 315 on all new 4rts & yes the cheese ones are thread locked in with permanent thread lock from manufacture ????