240 to 280mm Front Brake Disc Upgrade

6 years 5 months ago - 3 years 10 months ago #144946 by cairnsys
How To Fit Bigger Front Brakes


This How To describes how I fitted the MGF Mania 280mm Front discs to my Mk1 MGF. This is the kit of parts that you get, apart from the pads, you need to supply those yourself.





I also fitted new pads despite the ones coming off only being a few thousand miles old. For the sake of £20 it wasn’t worth putting them back.

Tools Required
12mm ring spanner or socket
15mm ring spanner or socket
10mm Hex (Allen key) socket
Torque wrench
Brake cleaner
Copper grease
Loctite or similar thread locking product
Piston rewinding tool (or large lever)
Disc removing ‘kit’ (assorted 10mm nuts, washers and bolts) or large hammer
Wire brush

Time Required
This will depend on whether or not you hit any snags such as seized bolts, discs etc. It took me about 2hours for the first side but I was stopping to take photographs. I also had a problem in that the caliper slide pin bolts snapped and I had to drill them out. The second side took about 45 minutes I would allow an hour per side to be on the safe side.


Firstly, do the obvious:

1. Chock rear wheels.

2. Jack car up,

3. Stabilise on axle stands.

4. Remove the road wheel.



5. Undo caliper slide pin bolts (12mm)

6. Remove the caliper and tie up out of the way taking care not to strain the brake hose.



7. Remove old pads.

8. Caliper carrier bolts (15mm) now need to be removed.





9. Caliper carriers were then removed and cleaned up using Brake Cleaner spray and wire brush. Mine were in a sorry state. Need to concentrate on the area that the pads sit in so that they are free to move.



10. Remove the retaining screws. I used an impact driver.



11. Remove the disc! I used the through bolt method described in the How To at:-
Brake Discs removal - How to remove rusted on discs
I’ve never had much success with the hammer technique.

12. Clean the hub and mating faces thoroughly. I used a wire brush on a grinder.

Before



After



The advice from MF Mania is to only use copper grease on the studs and not on the hub itself so I followed that advice. I know others recommend applying copper grease to the hub as well so I’ll leave that to personal choice. I put it on the hub face when I did the rear discs so time will tell which should be done when it comes to getting the discs off next!

14. Fit the extender block to the original caliper holder holes using the shorter Allen bolts with a washer either side of the caliper holder. It is essential to use Loctite (other thread locking materials are available) on the threads as these bolts are BZP so won’t rust in place like the originals. Tighten to 85Nm.



15. Clean the new discs surfaces to remove the preserving oil. I used Brake Cleaner but any oil solvent (petrol perhaps? – take care) would do.

16. Fit the discs, checking for correct alignment as best you can. They are a tight fit over the studs but will go on by ‘wiggling’ the disc as you ease it on.

Note that if you have grooved/drilled/dimpled discs these are sided. This picture is of the off side wheel. Ideally, you should use a dial run out gauge but I don’t have one so had to rely on eye. When you get the caliper back on it’s easier to check any run out, especially when the pads are in.

I couldn’t replace the retaining screws because the screw hole was in the wrong place on the disc. Shouldn’t be a problem as the discs are held in place by the wheel nuts anyway..

17. Refit the caliper holder using the longer Allen bolts, again using Loctite or similar and tighten to 85Nm.



18. Fit the new pads removing the backing from the pad shims and using copper grease on the ends of the pads only. This is a MGF Mania recommendation. Others put grease on the backs of the pads as well. Your choice of which to follow.

19. Lever the caliper piston back using a large screwdriver so that the caliper will fit over the new pads. Check the brake fluid level first so that it doesn’t overflow the reservoir. If it’s a bit full, you may have to remove some before you start pushing the piston back.

20. Refit the caliper to the holder and tighten the slider pin bolts to 45Nm.



21. Check for run out of the disc again. This is not that easy as the disc is now fairly loose on the studs.

22. Re-fit wheel and tighten nuts to 70Nm. (Recommendation now is to tighten to 100Nm) This is when you can check alignment because you can feel the wheel rotating evenly through the pads.



23. Road test being *very* careful and allowing for brakes not feeling 100%

24. The discs and pads need about 200 miles to bed in properly so it’s as well to avoid unnecessary hard braking during this time, though of course emergency braking is preferable to collision!

25. Job half done. Now repeat for the other side.

This shows the difference in size between the original 240mm and the new 280mm discs. Fairly significant!



The usual disclaimers apply - if you decide to follow this 'How To' and it all goes horribly wrong, don’t blame me ;)

Robin ;)
The following user(s) said Thank You: David Aiketgate, mogatrons, mgfmania, PQD44, Leigh Ping, Diesel Destroyer, Blow-in, Davem, Badger, c.steffan and 3 other people also said thanks.

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6 years 5 months ago #144950 by paulsmgf
Useful little how to well done
Glad you chucked the old pads as they would be rubbish (already destroyed by your old discs outer edge ) :)

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6 years 5 months ago #144965 by cairnsys
You should see the inside surface!!

Robin ;)

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6 years 5 months ago #144969 by PQD44
Great How To :beer:

Look forward to your report on the difference between stock and these once they are bedded in. :yesnod:

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6 years 5 months ago #144982 by The driving dutchman
Looks great but the calipers now use only the outer part of the disc so it's effect of being bigger is only partly used...I'm not really into this but new callipers will surely make this a much more costly upgrade.

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6 years 5 months ago #144992 by cairnsys

PQD44 wrote: Great How To :beer:

Look forward to your report on the difference between stock and these once they are bedded in. :yesnod:


Already significantly better though I haven't tested with hard braking yet of course. Once bedded I think they'll be excellent and resolve an issue I've always had with the F - that of poor braking performance.

Robin ;)

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6 years 5 months ago #144997 by PQD44

cairnsys wrote: .... resolve an issue I've always had with the F - that of poor braking performance.


Never a good sign when the best description of the brakes is ....adequate, just. :slapme:

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6 years 5 months ago - 6 years 5 months ago #145003 by paulsmgf
The ebay item id given is invalid, no result has been sent

www.ebay.co.uk/itm/02-MGTF-O-S-DRIVERSID...&hash=item1c417505ad

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6 years 5 months ago #145052 by mgfmania
Excellent 'How too', well written and photographed, MANY thanks Robin

Re. 21. Check for run out of the disc again. This is not that easy as the disc is now fairly loose on the studs.

Sorry, I'd forgotten that most people only have MG domed nuts. Standard brake fitting procedure at 'The Farm' is to pull new discs on with open wheel nuts and check run-out

For anyone able to travel to Knutsford: We have agreed £50 per end fitting Front/Rear 280mm upgrade + any other necessary items, pads, etc. by Alan Crossley - Motorsports Preperation ( www.ac-me.co.uk to be up and running soon!) or www.autotechcarrepairs.co.uk/ both are based on the same site as MGFMania

Regards

Peter

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