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MG MGF Technical - New Front Brakes

Hi,
I am pretty new to doing stuff to my MGF but have just ordered some new ebc turbo front discs and green stuff front pads(nice and cheap from spareshq.com!). Should I/Must I replace the rear discs and pads at the same time or can I just do the fronts? Any adverse effects?

Cheers...
Darryl P

the rears do much less work than the fronts so will be less worn and therefore may be left alone for the time being.
David

That said, the rears do do more work than on a Front engined car, due to having more weight over them. Don't think you would need new discs though, just get some decent pads, like the Greenstuff or better still, Mintex 1144s.

Steve.
Steve Childs

The rears do sufficiently "less work" that they can corrode (particularly on the "inside" face). Mine had bits flaking off, and the MOT man didn't like that...
Presumably, they don't get hot enough to dry the water / mud etc off...

My replacement rear disks have JUST arrived so I can fit them this pm and get the car back to pass its MOT!

I also bought a set of Green Stuff pads for the rear (I've got the older recommendation of Black Stuff's fitted) in case they've broken up at the same time as the disk failed. It seems that GS rears are quite a new addition to the range...

Neil.
Neil

Darryl, I don't think that there will be any ill effect of swapping the front discs whilst leaving alone at the rear. The 'turbo groove discs' or the visually very similar Roversport items do not actually improve braking efficiency (if anything, the gooves reduce the bake pad contact area!) The advantage with this design of disc is that it helps clear away excess brake dust from the pad/disc interface (which CAN reduce braking efficiency) and prevents the pads themselves glazing- a particular advantage for cars used in cities. For these reasons alone, it is worth upgrading all four discs. Plus, if replacement of the front is indicated by wear, then perhaps it would be a sensible precaution to replace the rears at the same time- to not to may prove to be a false economy.
Rob Bell

>> The rears do sufficiently "less work" that they can corrode (particularly on the "inside" face). <<

Sounds more like that the brake piston has siezed on the inside face of your rear brakes Neil, the same thing had happened on my 'F before I had them changed.

I would check the pistons n the caliper Neil, to make sure it hasn't seized, otherwise it will only happen again.

Steve.

Steve Childs

thanks for the input people....

Rob, so should I expect any noticable improvement in braking power once I do this (will take advice and get some new rear discs and pads too)? Also, the dealer said the front discs are worn but not really sure how to tell how worn they are?

Darryl
Darryl P

Yes, Steve, I was going to check that the caliper was moving OK while I had it apart.

There's only 1 piston in F brakes (both front and rear from looking at the manual), and "force" is transmitted to the pads by the caliper.

When I've seen a caliper stick in the past (not on the F), its usually the outside pad that does no work, not the inside.

The outside of my disks were fine, and they registered OK on the brake test rig (though I do need to adjust the handbrake cable up a bit too while I'm messing about with them...).

I'm still half expecting to find crumbled pads on the inner ones. I've heard black stuff's are a bit prone to that when they get hot...

Neil.
Neil

If you can have a complete brake fluid change,to get rid of any spongy pedel feeling,can make a big difference, if its not been changed for some time.
Joe

Yes, that's basically right Darryl; if you replace the discs with items that are the same size, you will not find them to improve braking to any significant degree. However, if you were to upgrade the pad material at the same time, this WOULD improve braking as different pads have different co-efficients of friction and different temperature ratings.

I personally do not rate EBC black stuff pads- they simply wear far too rapidly- and are certainly prone to disintegration as Neil mentioned. In fact, even the far superior EBC green pads are prone to this- but these are the pads I recommend to change to. These have been available for all four corners of the car for some time- so if replacing the discs, have the pads changed for the same time.

If you are wanting pads from an alternative source, do try the Mintex range. Steve and Dave use the 1144s and they seem an excellent fast road pad that are far better suited to the occassional track day (EBC Greens tend to fry a bit with this kind of use). Personally I have 1177 race pads... and they are teerrrriiifffiic! But then they should be for the price! LOL

BTW I agree with Joe's comment regarding the complete replacement of brake fluid- makes a big difference on older cars where the fluid will have absorbed atmosheric water...
Rob Bell

This thread was discussed on 06/02/2002

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