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MG MGF Technical - Changing Brakes
|I'm determined to stop using the garage to do everything on my car cos they charge so much money for the smallest thing. I managed to put the K&N on myself (not hard is it) and next i want to change my own brake pads and maybe discs. Is this easy, and if it is how do i do, and also what tools do i need to do it.|
Any help would be greatly appreciated
Socket set + Torque wrench.
A big "G" glamp (or that's what I always use for compressing the pistons!)
A "Pin wrench" for the back ones. This one had me puzzled for a while but I ended up using the pin wrench from my angle grinder which did the job perfectly.
Some string to tie the back calipers up with....
Brake cleaning spray.
I use a syringe body to take excess brake fluid out of the master cylinder...
Copper grease (once again, I always use it where the pads bear onto the calipers, but its not strictly necessary.
If you really feel the need to check the disk thickness (is it worn?) then a micrometer is probably the best implement (I admit I do have one, but I didn't check the disks at only 38k miles and one set of pads from new)
The front end:
1. Jack up car, remove wheel and put under suspension (just in case the jack gives way - I don't own any axle stands)
2. Remove the bottom bolt from the rear of the caliper. Make sure you're "unscrewing it" - as its at the rear its easy to try and tighten it!
3. hinge the caliper out of the way to expose the pads.
4. Remove them and throw away. They do have shims on the back. My front shims were quite distorted and the paint fused to the back of the pads, however discussions led me to believe that unless you're getting brake squeel, they probably aren't needed.
5. Clean up the area with the cleaner and rag etc (normal caution about the dust - don't inhale it!)
6. Compress the piston back into the caliper with the G clamp. Watch the master cylinder to make sure you don't cause it to overflow (the book recommends putting rag around it to catch any lost fluid)
7. Check the fit of the pad into the caliper. If its tight, it may well be there's a little too much paint on the sides of the backing plate - a file will soon reduce this!
8. Smear of copper grease on the places where the pad contacts the caliper (v.small amount - you don't want it on the braking surfaces!)
9. Smear of copper grease on the part of the piston that contacts the pad.
10. Swing the caliper back over the pads and refit the bottom bolt. Torque to (I THINK IT IS - I don't have my book to hand!) 35Nm.... Don't overtighten, as alloy isn't that strong... A smear of copper on the threads isn't a bad idea while you've got it to hand.
11. Press the brake pedal hard several times.
12. Refit the wheel etc...
13 on to the other side....
14 Drive CAREFULLY for a couple of hundred miles to allow the pads to bed in and match the profile of the disk.
The rear is almost the same.
The only differences are:
0. Release the handbrake and chock the wheels
1. remove BOTH bolts, and then tie the caliper up out of the way (don't let it hang by the hoses)
2. You have to SCREW the piston back using the pin spanner at the same time as you press it back with your thumb.
3. The shims on the back of the pads were in much better condition on the back of my car, so I undid them from the pads and reused them...
4. When you're doing the back ones will be when you probably have "too much" brake fluid. Be careful as its rather corrosive to paintwork....
I'm sure others will point out the steps I've missed out - its a couple of weeks since I did mine with Green/Black stuff.
I assume when you say book - you mean the workshop manual - is it worth getting one of my own?
and to a novice that sounds like hard work - am i just being a wimp
|Sounds more difficult than it actually is - but do remember that brakes are there to stop you!|
I would suggest that if you have not done this sort of thing before to get help the first time - or even do one of the car maintenance course that most local adult colleges run.
Yes the workshop manual is worth its money.
|A course would be a good idea, i shall try and find one.|
|Very good advice from Ted.|
Old timers will probably get away without the G clamp and the torque wrench but forget to remove excess brake fluid from master cyl !!
I know I was that guy :-)
|Nice instructions Neil :o)|
Rog also wrote some detailed notes on front pad replacement that can be found in the archives (and also on Richard Eaton's website, http://www.mgfworld.com).
To change the discs is a doddle too- Rog helped me with my front disc replacement, and it really did appear straight forward.
Once the calipers are removed, the discs are held in place with two counter-sunk, phillips headed screws. The function of these is simply to keep the discs located in position- the clamping force is brought to bear by torquing of the road wheels to the hub, sandwiching the disc into position. The disc should simply pull free. Clean the mating surfaces, lightly copper grease, and put the new disc into position. It should go on true- if not remove, and ensure that the hub and disc are both clear of debris. Once the disc is in position (judicious use of a hammer to drift the disc into place may be helpful), replace the location screws, and reassemble the calipers as Neil has described. Job done. :o)
Hopefully have some piccies showing Rog's handiwork. It'll all be part of a website update... Crumbs! So much to do!!!
indeed, thats not difficult. .. If you don't brake any bolt ;-)
Getting off the discs is another story. Novice should IMO really keep their hands off !!
Nick, have you got the right english name for this both tools which are immidiate required ?
Getting off the bolts which hold the discs in place on the axle plate:
- a Phillips Screwdriver insert(Bit) fitted to a Driver which needs a strong hit. On that hit the phillips bit turns.
That tool loosens the Philips screw only.
In German langusge: 'Schlag-Schrauber'
Pulling the discs from the cone:
- A very wide G-Clamp (two or three arms with a large diameter centre bolt.
The center bolt needs to be screwed to the centre hole of the axle until the Clamp meets and grips the outer diameter of the disc. Then turn the Quad head bolt of the G-Clamp with a wrench strong until the disc slips from the axle cone.
In German Language 'Abzieher'
*g* Now I would like to be amazed about the short two right english descriptions for the above both tools.
"Impact Screwdriver" and "Hub puller" I think Dieter.
Replaced discs and pads on an 'F only last weekend.
(In fact it was Rob and Carol's beloved Maggie for those in the know...)
Pads are v.v.easy to do.
Discs are easy too, but we needed the impact screwdriver and could
have done with a hub puller.
In the end a four pound hammer helped lots! :o)
Took Rob and I about 2 hours to do the first side (a learning experience) and a
whole 30-40 minutes to do the second side! Dead easy!
Advice: When taking the discs off it is useless repeatedly hitting one side.
You need to keep turning the disc and hitting all round to get them off.
Hope that makes sense...
PS. Think it's a 12 and 14 mm socket that's needed. :o)
|With awkward disc removal it is not a good idea to use a steel hammer to clout the disc. This can and does encourage steel fragments to fracture and fly off. The amount of force sometimes needed to remove the disc is enought o promote this dangerous condition. |
The solution is to use a copper headed hammer or have an insulator between the disc and steel hammer, such as a piece of wood. As Paul says, rotate the disc between each hit. turn 180 degrees at a time for half a dozen times, then 90 dgrees for one, and back to 180 degrees. The disc has an interference fit between the hub edge and the inner face of the disc bell, not the disc hole centre onto the drive flange.
the hub puller is the best solution IMO.
Agreed Roger. Quickly found this out and used a good old fasioned bit of wood
between the four pound hammer and the disc.
Found out that on the Rover 218 (which has the same discs ???) there are two 8mm
bolt holes on the disc that you screw two bolts into. They will push the disc off
for you as you screw them in.
A simple but effective *built in* solution. Why doesn't the 'F have this ?
|>Why doesn't the 'F have this ?|
Great solution :)
Hope the suppliers of aftermarket brake disks read it. (Hi Mike)
Guess three thread holes M8 would be the good.
Anyway, I'll keep it in my mind for a brake disk chage in the future. Drilling the thread holes before mounting the disk isn't that difficult.
|Prtobably never been a consideration since these discs have been in production since 1983 and at that time the nbeed wasn't seen for such niceties. The Rover 200 series from 1989 to the 25 today uses a 22mm larger diameter disc and system that was in production only from 1989, by which time the pitfalls of disc changing were known and the fact that this was Honda influenced period. Note how many Japanese cars have little things like this to ease maintenance. |
Even so removal has never been a real problem so the costs of altering the production process have not been justified. I do hope that one area of MGF upgrades from Longbridge sees to it that the brakes are given more reserve through being enlarged. I know they will be for the hot models I know are on the way, but I would hope that production volume sense sees to it that all are upgraded, even the 1.6 base model.
This thread was discussed between 08/12/2000 and 10/12/2000
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