Changing front discs - step by step guide?

[finmac]

Wondered if someone could link me to a guide anywhere please?

Doesnt look complicated but its often easier to read up first!

 

cheers

[SM25T]

I hoped Myles had done this on the Alcester Racing Sevens site .... but no.

Assume you know how and where to jack and secure the front end if the car.

Loosen wheel nuts

Raise car and remove front wheels.

Remove security clips from caliper pins and pull pins out.

Slide pads out, noting position of any shims behind them.

Undo caliper  retaining bolts (2) noting position of any washers.

Lift caliper off disc and tie or tape it to the suspension.

Remove dust cap over hub bearing if fitted.

Straighten split pin legs and remove it.

Undo big nut and remove it noting position of washers behind.

Pull hub and disc off the stub axle and catch bearing races and seals.

Put wheel face down on floor and stand hub studs into holes in wheel. This holds hub while you loosen bolts.

if you have socket head cap screws holding the disc on ... use appropriate hex bit in biggest ratchet to undo them. If you have then headed hex head bolts, use a six sided socket ... not 12 cornered type .... you may have to grind end of socket flat to make sure you get enough purchase. Impact driver or impact gun may help. If bolts loctited heavily .... apply heat around hub where bolt sits and try again when really hot. Electric hot air gun will do.

Make sure disc mounting flange is spotless before fitting new discs and clean any coating off new discs.

Use a spot of loctite on disc holding bolts. Change to socket cap head if you had old shallow hex head type.

Reassembly is reverse of above. 

Suggest cleaning old grease out of hub bore and repacking bearings well with your fingers. No need to fill the hub. ...... I just put a dollop in there.

Do you know how to adjust bearings ?

Ian

 

 

[Nigel Riches]

Hi Finmac. 

A bit more information about the type of 7 you have might get more response.

Generally it's a case of get it off the ground, remove wheels, remove bolts holding brake calliper to the upright, remove bearing dust cap from the centre of the hub, remove the split pin in the castellated nut, remove nut, the disc and outer bearing will now be removable, the outer race of the inboard bearing will also come away. 

The disc is held onto the hub by four bolts, inside the "top hat", remove these and install the new disc. 

Assembly is the reverse of disassembly, to quote Mr. Haynes famous words, however be sure to torque the bolts to the correct amount, which I can't find just now. Ok got it, disc / hub bolt 22 - 27 lb ft, and the bolts to attach the calliper to the upright is 40 - 45 lb ft, well according to my 1996 Caterham assembly guide. 

The castellated nut on the stub axle is tightened to the point where rotational resistance is felt, then backed off to the nearest slot allowing the split pin (a new one each time) to be installed, don't forget to bend the ends apart. 

Hope this helps. 

Regards, Nigel. 

Damn,  beaten to it by Ian. 

 

[finmac]

Thanks guys, thats brilliant and all before 8am. The power of BC!

Reading the above I think I have just two more questions,  regarding the bearings, 

1. I take it any decent besring grease will suffice?

2. When retightening the castellated nut, is this done by hand or gently using a socket? And at the first point of resitance being felt is that when you stop and turn it back to the first hole?

thanks again guys cheers Finlay

 

[SM25T]

Finlay .... 0351 ... it was causing you sleepless nights !

Any bearing grease will do.

Tighten with socket and ratchet while turning hub. Then loosen and tighten with socket until it just contacts. You should be able to turn hub ok. Fit wheel and check no (or minimal) play at 12 and 6 o'clock positions. Then fit split pin and bend legs. Do this without brake pads. Note there are two holes in stub axle. Pick whichever suits best.

Now that I don't travel any more on business, say hi to the guys at BTS Grangemouth from me when you next see them.

Ian James.

[Sim]

Just to be clear - the 'first point of resistance' is when trying to rotate the wheel - it's  not resistance to tightening the nut 

 

Simon

[finmac]

Thanks again guys, started the job this afternoon and its proving fairly simple (so far anyway!).

Will do re BTS Ian, they do  a lot of work for me now, so am in and out fairly regularly in person. Cheers Finlay

[R400CAT]

Thanks for this guys.   Gonna change discs today, and this has certainly helped.

 

Paul

[DJ.]

I found that I needed to tighten the hub nut more than I imagined, becuse the inner part of the bearing started to spin on the stub axle when I backed the nut off. Just regreased them this winter and they were fine after 20,000 miles so I must have got it right