simonbuk wrote:Ok, were your fronts a straight swap ? Just went to put the hispec on my car, the bolts on the existing caliper are massive !! The head of the bolt is over 22mm (I don't have anything bigger if course), but the bolts that came off the hispecs are alot smaller. Or should I say the allen key heads are a lot smaller, maybe the bolt size/thread is the same but can't see on the existing caliper ?
Straight swap that didn't take long but was also changing discs to 295mm re-drilled Subaru that came with them. Quite straight forward with the right tools & equipment ...
Are you changing discs? - most HiSpecs on M100's seem to use bigger discs.
Order of play for me was :
Jack up car on full lock so the caliper to work on is more accessible and remove wheel.
Remove caps and undo socket head bolts that hold caliper onto mounting bracket and remove flexi hose clip from wishbone bracket - remove caliper and stand on block of wood or axle stand at back of wheel arch.
Remove socket screw that holds disc to hub and remove disc.
Remove two bolts that hold caliper bracket to hub carrier - as you say, they are big, M12 thread, and not removed for servicing the brakes so probably still as fitted in factory. Felt like they'd been torqued to 100 ft lbs with Loctite but 2 foot long 1/2" square drive breaker bar 'cracked' them.
Replace with HiSpec aluminium bracket and bolt to hub carrier with M12 Cap Head Bolts with spring steel washers to stop digging into aluminium, Loctite on threads and torque to 100Nm.
Fit 'bigger disc' and use wheel bolts taper to centralise it and replace & tighten socket screw, and check disc with dial gauge for eccentricity and run out... if OK proceed to ...
Fit HiSpec Caliper with hose by mounting on aluminium bracket with M10 Cap Head Bolts & washers, Loctite & torque to 60Nm. Fit pads to caliper in their original positions.
Open both inner and outer bleed nipples on HiSpec caliper 1/2 turn.
Remove flexi hose clip from wheel arch bracket and unscrew hose to pipe union - brake fluid will come out so prepare for spillage. Can now get OE caliper & hose out of wheel arch and fit braided hose from HiSpec caliper to pipe and then clip to bracket. Keep an eye on fluid level in master cylinder as fluid is filling both pistons of the HiSpec caliper. (HiSpec suggest calipers will fill under gravity but it will take several minutes.)
Clip hose to wishbone bracket and check position of hose with respect to rubbing anywhere when turning from lock to lock.
When fluid appeared at the bleed nipples I closed them finger tight and fitted my bleed tubes - big bore screen wash tubing with aquarium one way valves, opened them again and pumped with the brake pedal to check no air left in system.
(Lotus Service schedule has 'renew brake fluid at 12,000 mile service' (ha ha) 'or every 12 months', which I'm sure comes sooner, so I have no worries about flushing out old brake fluid when I'm working on the brakes.)
Close bleed nipples, remove tubes, fit dust caps, replace wheel and do further checks for hose clearance to wheel and tyre... if OK, job done.
and I think it took me longer to type that than to do the job itself .....
