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mgf
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Discussion Starter #1 (Edited)
Some of you may have read already, than rather than buying new or recon rear brake calipers, i decided i would like to do it myself
so i bought two rear wheel assemblies from a 61K 2001 MGF - the same year as my own cars.. from EBay, for £25 each.

the two wheel assemblies as unpacked.

http://www.incony.org/webpics/MGFRearBrakeAssemblies 001a.jpg


its kinda sad that these were once on someone's pride and joy, and now lie here chopped off.. but.. for me, for £25 each i can see my moneys worth already, the disks are good, the pads are good, and therefore i already think that the calipers are serviceable..and i am pretty sure that the other bits and bobs still in one piece, may be of use too..


http://www.incony.org/webpics/MGFRearBrakeAssemblies 002a.jpg

so.. now begins the refurbishment of the calipers so i will start at number 1, and as i do things post pics etc etc..
 

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mgf
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Discussion Starter #5
£50 the pair, MB, is what they cost me... :)

so certainly.. if you can get a matched pair for £25 you would be quids in...
 

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mgf
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Discussion Starter #7 (Edited)
1.
Look here so you have usefull information from someone who has already done it:

https://forums.mg-rover.org/blog.php?b=741

2. Clean up the assembly as bought without taking anything off, so you can see the condition of things before you try to dismantle them.
its best that they are dry, simply because dust is easy to remove with a paint brush.. but if the assembly is caked in grease then a degreaser and a wash, before running over the dry assemblies with a selection of rotary wire brushes in a drill, is easy to do and worth the effort..

http://www.incony.org/webpics/MGFRearBrakeSept12 002a.jpg


http://www.incony.org/webpics/MGFRearBrakeSept12 003a.jpg

3. The caliper securing bolts need a 14mm socket, and wether you are doing this off the car, or on it, a long bar will assist in cracking the torque

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 001a.jpg

Releasing both caliper bolts means that the caliper complete with the brake pipe still connected , and the handbrake still connected
will ease of the brake disk.. for me its easy, since the wheel is off the car.

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 002a.jpg
At this point, you want to put it back on again and finger tighten
the bolts.. knowing that they will now just undo easily, because...

You need to ensure that if the brake line, does not get damage or stress, that you remove it.. mine is already cut off.. but i am showing what i would do, if it were on the car.

Same long bar and socket - 14mm.. will crack open the brake line bolt.

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 003a.jpg

when you do that... fluid will start to leak.. it can be helped.. some sawdust on the ground... will stop it going everywhere..
but if you continue to release it.. you will loose a lot of fluid from the reservoir... so..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 004a.jpg

a bolt of the same size..wrapped in ptfe tape,
sufficiently to be a snug fit in the brake line coupling will mean the line will either just weep a little fluid or stop completely, enabling you to continue, without a great loss of fluid, or risk damaging the pipe by clamping it..


http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 006a.jpg

With the brake line now free not leaking fluid everywhere, and under no stress or risk of damage, one can , with the caliper still in place on the disk, release the bolts that secure the two parts of the caliper together... still - remember.. ive not touched the handbrake at all, leave well enough alone.. deal with one thing at a time..
As this picture shows, you will need a 12mm socket, and depending on the corrosion, a long bar to crack the torque on the bolts.

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 006a.jpg

with those bolts removed, the caliper will slide apart.. and the pads will be free..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 008a.jpg

more fettling with the rotary wire brush enables you to see the status of the pads.. if they are in good nick, like these they almost fall out..
dont be tempted yet to look inside those rubber seals... but there are some checks you can make on the operation..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 009a.jpg

with the pads out, one can remove the stainless anti rattle / protectors

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 011a.jpg


and check the operation of the caliper by pulling on the mechanism.. it should move freely.

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 012a.jpg

one can now see the piston in the other - main half of the caliper, so before one is curious as to what it looks like.. more fettling with the rotary wire brush..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 010a.jpg

if one does not have the correct piston rotation tool, or cant be arsed to loose half a day going to get one, then a large flat blade screwdriver will tell one immediately if the piston is siezed in its housing. - turn clockwise to turn in..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 013a.jpg

and anticlockwise to turn it out

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 014a.jpg

continuing to turn anticlockwise will free the piston..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 014a.jpg

when it comes free, the rubber dust cover stays in place... if you are not renewing this ( you should ) then a tywrap end
- a non damaging stiff flexible bit of plastic.. will release the seal from the piston..

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 015a.jpg

and the piston will slide out...

http://www.incony.org/webpics/MGFRearBrakeStep2Sept12 016a.jpg



remember you still have not touched the handbrake part.. leave it alone..

now at least you know.. the caliper is not seized, the pads are ok. the disks are a little worn,
but serviceable.. you cant find anything of such concern this moment that you think the caliper
is unserviceable..

time for a break..

put all the parts in a Kellys Clotted Ice Cream Box, especially provided by Tesco for the purpose...
so that you can start the next step.. a look at the handbrake mechanism..

www.incony.org/webpics/MGFRearBrakeStep2Sept12 017a.jpg
 

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Noooo! Was reading intently for the handbrake part and you've given a cliffhanger! Brilliant piece mate- like the tip about the bolt in ptfe tape to stop the fluid loss. Look forward to the next installment. (sure beats 50 Shade of Poop)
 

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mgf
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Discussion Starter #10 (Edited)
Step3. The Handbrake assembly:

This is something i`ve only partially investigated before, and pretty much reached the same point, with the brake caliper on the car... and dismantling it there. With the Caliper off the car.. i can venture more, so this is Step3.

1. Remove the securing R clip from the pin that secures the handbrake cable to the caliper.
This is a distinctly fabricated R pin.. one end is curved around.. do not think that has no reason, and one can just use any split pin or bit of wire.. there is a reason its thats shape.

http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012001a.jpg

the reason is, the pin is in close proximity to the handbrake mechanism.. and under no situation must it be able to interfere or change that.... if it can the consequence might be this: :)

Today, knowing that my initial investigation of my Freestyle`s hand brake problem, resulted in me, cleaning and lubing the handbrake mechanism at the caliper, AND, that on doing so. i snapped the R pin on removal.. and it was scrap.. so i replaced it with a bit of sprung steel wire, i drove from my house to the local supermarket- 3 miles. At the first junction i came to a stop at.. i sensed something was wrong.. the car was not rolling to a stop.. on idle with the clutch depressed, it was stopping like i had the brake on..

I pulled into the supermarket car park and had a look.. thinking the handbrake was stuck on.. (my whole reason for this post and investigation..)

i was right.. but the cause was mine.. the wire i had used.. had turned in the pin.. and when i released the handbrake cable it fouled the mechanism... and stopped the handbrake from releasing.. - the result? i drove three miles with the handbrake partially on.. on one wheel.. and it got very very hot.... i released the wire.. and the handbrake released... i was fortunate i did not go further before i sensed the problem.. in three miles, the brake and disk were so hot.. i would have burnt myself touching them..

SO.. the pin is this shape so it wont turn in any direction and foul the mechanism.. remember that.. :)

This pic is a little out of focus.. tough luck... the pin should be free to remove now, certainly if it has been lubed regularly... mine would not turn or remove easily... i had to put on freeing lube and even then after a wait.. i used a punch and a lump hammer to knock it out..


http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012002a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012003a.jpg

with the pin free. i decided to remove the brake cable fixing... - if one is doing this on the car.. its not required, i just did it to give me better access.

www.incony.org/webpics/MGFRearBrakeStep3Sept2012004a.jpg

The bolts were siezed in.. and from the above pic, one can see that on getting them free, the bolt heads were ******ed . this was after using penetrating fluid, and first a long bar, then molegrips... i got close to using a cutting disc to cut off the head when it gave way, and i was able to release it.

The next thing was to release the spring.. its easy.. a small screwdriver put in the position shown, will just lever it free.

http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012005a.jpg

a slight lever, and out it comes

http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012006a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012007a.jpg

with the spring free. one can see what is behind it.. the handbrake lever, and itsc securing nut.. another blurred pic... such is life...

www.incony.org/webpics/MGFRearBrakeStep3Sept2012009a.jpg

The brake mechanism should turn easily up to its stop.. no friction.. and one can do that by hand, feeling the pressure of the integral return spring, inside the mechanism.

www.incony.org/webpics/MGFRearBrakeStep3Sept2012010a.jpg

Once can then release the nut, that secures that operating arm, and remove the nut and the arm.. the arm is a tight fit,
it wont come off easily, and needs an application of freeing lube, and a substantial tap wiith a punch, a backwards and forwards motion - tilting on its axis.

http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012011a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012012a.jpg



When the arm is off, one can again check the operation of the handbrake mechanism.. using a spanner..



http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012013a.jpg


But.. the piston assembly wont come out..

its held in place internally.. and though one can move it out, and push it in.. it will not come out.

the reason for that is this..


http://www.incony.org/webpics/MGFRearBrakeStep3Sept2012008a.jpg


looking into the piston housing, one can see a circlip, deep inside at the bottom..

non of my own circlip pliers could reach it.. and release it.. it needs a specific long reach pair..

so monday.. i need to get some..

watch this space..:)
 

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Discussion Starter #11 (Edited)
Step 4.

Not for the faint hearted, and not required by anyone just servicing the rear brake.. ( i think ! )

No motor factors near me, could supply a circlip tool, with a long enough reach to get to the circlips in the piston housing..

So, i made one.. using a pair of cheapy BnQ long nose pliers with a tiny hole drilled into each tip end that i could put in a couple of ends cut off from a hex key ( hard steel ) that would fit the circlips inside..

i was kinda hoping, that when i got the circlips free, the whole thing would come apart...

it doesnt.. this is as much.. left to right, as came out.. nothing more, would freely come out of the bore..


http://www.incony.org/webpics/MGFRearBrakeStep4Sept12 001a.jpg

and this is what one can see inside the bore...


http://www.incony.org/webpics/MGFRearBrakeStep4Sept12 002a.jpg

so, with nothing gained easily by taking out those circlips, i cant see a way to improve or refurbish anything further.. and no reason anyone needs to do what ive done..

IF ANYONE KNOWS MORE THAT CAN BE DONE WITHOUT SIMPLE TOOLS ON A DIY BASIS< BEFORE I PUT THE ASSEMBLY BACK TOGETHER>>> PLEASE TELL ME>>> :)

the next step will follow soon... :)
 

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Well i love your honesty!:clap:
I was going to ask you if it was really necessary to strip your callipers down so much.
But i am much the same i guess, i like to see whats inside things.

To be honest when i refurbed my brakes and i am being generous calling it that, i just spilt the calliper into its 2 halves,greased the sliders and boot, and rammed my spray grease pipe under the piston boot and gave it a good squirt.
Then just wound the piston in and out a fair bit to make sure everything was loosened off and moving nicely.
Was replacing the disks and pads at the time, put it all back together and they work great for standard brakes.
Mr Mot tester said they were perfoming really well compared to some much fancier brakes he had seen on Tf's assuming he meant AP's.
 

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Discussion Starter #13 (Edited)
Not seen in the first photo of Step4, in the parts laid out... is the push plate for the handbrake.. its still inside the bore...

and shows in photo2... of the bore..

that plate, once i washed the inside of the bore, with brake cleaner.. just dropped out.

thats why the first circlip, ( shown nearest to the bore in Pic1) , is there.

I filled the assembly with brake cleaner.. tried the action of the now loose handbrake spindle arm.. and no brake cleaner came out of its housing.. so that means there might be a seal in there i cant reach.. or some non return thing..

but there is no obvious way to get that brake arm piston part out..


Info added - 7/9/12 since i got the right info to dismantle...

taking the bleed nipple out


http://www.incony.org/webpics/MGFRearBrakeStep5Sept12 001a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep5Sept12 002a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep5Sept2012003a.jpg



http://www.incony.org/webpics/MGFRearBrakeStep5Sept2012004a.jpg
 

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Excellent write-up, a worthy successor to the crown of CJJ, as to the calliper

1. Probably a good thing that DIY ers arrive at a brick wall at that point rather than arrive at a brick wall........with no brakes.

2. It,s nice to know that some things will still remain a secret, especially things this crucial

Good effort
 

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Discussion Starter #15 (Edited)
OH NO! ARRRRRRRRGH !

OK.. a step forwards... sadly means a step backwards sometimes

i post this pic because:

http://http://www.incony.org/webpics/MGFRearBrakeStep5Sept2012007a.jpg

As you have read, i took out as much of the piston bore bits as i could...

i was correct in doing so.. since if you study the above pic, with all the parts cleaned and a flash coat of silver applied, and all the new seals laid out from the kit purchased...

you will see two small O rings below the piston...

OK.. the larger one, goes inside the piston itself..

The smaller one, goes on the end of the piston pushrod :(

Why is that bad news? ive just reassembled that handbrake spring assembly back together.. a pig of a job to figure out how to get it apart.. and a pig of a job to get back together...

now ive got to take it apart again to replace that O ring.. and put it back together again...

So.. Step 4 continues this moment..

once i found those O rings in the Kit.. i phoned up BIGG RED www.bigred.co.uk Tel 01905 428793 to discover where they went...
and now i know..
so..

i am going to have to take the insides of the caliper piston bore apart again.. and will post some more pics...
 

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Discussion Starter #16 (Edited)
This pic shows the piston internal disassembled... the O ring seal.. is to block the ingress of water, since the piston has a breather hole, in the seal flange that when the seal is in place one cannot see..

It also shows the sequence of parts as they come out, after removing the circlip..
above that one can see the relatively easy method of compressing the handbrake piston...

www.incony.org/webpics/MGFRearBrakeSpringRemovalStep4Sept2012 002a.jpg

The real difficult part is getting the circlip out.. no normal ciclip pliers will reach it..
and the first attempt i made only really worked once because i was lucky...

http://www.incony.org/webpics/MGFRearBrakeSpringRemovalStep4Sept2012 003a.jpg

its going to need a better "thing" :) than i have right now to free the circlip reliably i need to either buy one specific, or make a more purpose full tool..
 

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Discussion Starter #18 (Edited)
the right angle long nose circlip pliers listed above will reach, and they are right angle not curved..

so ive bought some.. on their way today... thats a cost i will add to the total bill when this saga is done..

:)


Looking at Stations excellent disassembly blog, that i posted a link to.. i really should have known that i had not reached the
end point.. before i said i had..
Station got the whole thing apart, a credit to Station, since that brake caliper was in far worse nick than mine..


now.. looking again at that.. i know the whole thing will come apart.. and there are no trade secrets..

Thanks Station for your hard work... for me ignorance was bliss.. and i paid for it..
 

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Discussion Starter #19 (Edited)
So, The long reach, 90 degree angle circlip (snap ring ) pliers arrived this morning, so i was quickly able to release the piston bore spring mechanism and its backing disk etc...

http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 001a.jpg

with that done easily, (though still locating the circlip holes isnt easy and those pliers are vital... )

i looked at releasing the piston drive arm, from the centre of the piston bore

having spoke with BIGGRED yesterday, i knew they put the piston threaded bore insert in, and an easy levering of that would get it out...

it did.. the thin spanner and a tap with a hammer and out it came, with the o ring and pin attached..


http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 002a.jpg


http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 004a.jpg

with that done, i could now look at the handbrake actuator mechanism..


www.incony.org/webpics/MGFRearBrakeStep6Sept2012 007a.jpg

http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 006a.jpg

its apparent now how the rotation of that actuator, works when one pulls on the handbrake
the actuator turns in its needle roller enclosed shaft.., but the needle rollers dont fill the whole shaft circumference since the pin the actuator
is pushing, goes through a hole in that bore... into the piston push rod...

so when you pull the handbrake you push the piston... and that spring assembly sitting in the bore.. how the piston is kept in the right place,
all the time..

The O ring that i missed replacing yesterday.. on the piston drive shaft - is VITAL.. since it prevents fluid escaping into the handbrake actuator, and grease / dirt and lubricant that gets into the actuator bore, from getting into the piston bore..

when you squirt lubricant into that actuator.... the risk is that you might degrade that O Ring on the drive arm, and therefore though you free the actuator, IF fluid or lubricant gets past that O ring, the brake wont work well.. and it tells me why though i got a rear brake with an iffy actuator working again, without doing this disassembly, (just squirting WD40 past the actuators outside seal...) maybe.. doing that got crap, past the O ring... or even it had already started failing.. and why i couldnt get the handbrake to reach MOT spec.. even though it worked better.

looking down the bore, where the piston drive shaft goes with its O ring on it.. one can see the needle rollers in the actuator hole, where the pin goes into the actuator..

http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 008a.jpg


This pic.. is the whole thing with the main caliper body, laid out in assembly..

http://www.incony.org/webpics/MGFRearBrakeStep6Sept2012 005a.jpg

i need to clean and reassemble it all now.. paying attention particularly on making sure that needle roller bearing assembly is spotless, and the pin and its bore is spotless
before using some lube of the right kind.. i am going to look it up.. i think brake grease is specific..

I can Start Step5 Soon... :)
 

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Quite a task you are undertaking there sir and hats off to you, the full rear caliper refurb guide is something that this forum has been lacking.
 
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