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mgf
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Refiting push rod

Followed your refurb to strip my own caliper but have hit upon a problem which I hope you will have the answer to
Try as I may I cannot compress the spring (and cage) on the piston shaft to engage the circlip. The spring will only compress about 5mm max and i seem to be starting at a position where I need to compress the spring by at least 10mm.
Any ideas

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mgf
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Help with caliper re-build

Incony
Thanks for the detail its been invaluable whilst I have worked my way through both caliper rebuilds on my '97 MGF. However I am stuck in that I am finding it impossible to exert enough pressure to compress the spring(cage) in order to get the final circlip in place. The spring has about 5mm of compression but I'm looking to create a movement of around 10mm. I have tried circlip pliers one side and a blunted screwdriver pressing down on the other side of the circlip but I'm still way short. Any ideas please?
 

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mgf
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Discussion Starter #43 (Edited)
Incony
Thanks for the detail its been invaluable whilst I have worked my way through both caliper rebuilds on my '97 MGF. However I am stuck in that I am finding it impossible to exert enough pressure to compress the spring(cage) in order to get the final circlip in place. The spring has about 5mm of compression but I'm looking to create a movement of around 10mm. I have tried circlip pliers one side and a blunted screwdriver pressing down on the other side of the circlip but I'm still way short. Any ideas please?
yeah.. its a very close fit.. it comes apart so easily, but is the gods decision to refit..

i cant give you more than i have.. i did it using the tools and method i give. i know that leaves you with a problem.. you cant.. so you - right this mo Mike, are the problem solver.. what worked for me, doesnt work for you.. all i would say.. is if you have a solution.. link my post and your posts to it.. so others can follow your path.. as i did.. and helped you reach this point..

its possible you are not assembling in the right order Mike.. so check that.. since if in the wrong order.. it wont fit.

dont be thinking it needs more force.. thats wrong.. if it doesnt go together easily with the tools you have, as easily as it came apart.. then you are doing it wrong.. that might mean something you have already done, but fits.. is wrong.. so you mount a conflict.. so..

take it apart.. restart..

if still it wont go together.. as it came apart.. you have found a new problem i did not see.. so i cant offer a solution to something i do not know..#

if you give me a link to my post step.. that you are having a problem with.. maybe i can offer more info from memory.. i know that that circlip has to be in exactly the right place to click shut.. else it wont. there is no option i can remember.. it does or it doesnt.

can you give me the image link mike?
 

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I also refurbed my rear calipers last year after reading this thread but when I started using the car again a few weeks ago I noticed the brakes were very spongy and did not inspire any confidence so I did a little investigation and found one of the rears was leaking past the piston seals. I'm not sure if I did something wrong or the brakes I bought were too far gone but I decided to cut my losses and go for these.
http://www.ebay.co.uk/itm/371263926851?_trksid=p2060353.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT
I will report back on quality when they arrive but as my MOT is due in a couple of weeks I can't afford to mess about.

BTW when squeezing the cage back in you must make sure it is perfectly centred and doesn't catch on the edge which holds the circlip. You must also make sure all the flanges of the cage have not bent up by getting it wrong previously, I spent quite a while doing this bit too and had to straighten edges on the cage several times. From memory I think you must also ensure the centre screw can go up through the socket or whatever it is you are using to push the cage in but not 100% sure about that.
 

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mgf
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Discussion Starter #45
I also refurbed my rear calipers last year after reading this thread but when I started using the car again a few weeks ago I noticed the brakes were very spongy and did not inspire any confidence so I did a little investigation and found one of the rears was leaking past the piston seals. I'm not sure if I did something wrong or the brakes I bought were too far gone but I decided to cut my losses and go for these.
http://www.ebay.co.uk/itm/371263926851?_trksid=p2060353.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT
I will report back on quality when they arrive but as my MOT is due in a couple of weeks I can't afford to mess about.

BTW when squeezing the cage back in you must make sure it is perfectly centred and doesn't catch on the edge which holds the circlip. You must also make sure all the flanges of the cage have not bent up by getting it wrong previously, I spent quite a while doing this bit too and had to straighten edges on the cage several times. From memory I think you must also ensure the centre screw can go up through the socket or whatever it is you are using to push the cage in but not 100% sure about that.
i agree with Alibro, if you get it wrong, the cage will deform.. it has to be a perfect fit.. and like Alibro, i had to try more than once, i deformed the cage. That said.. those calipers that i refurbished have not needed dismantling since the date of the original post... I would say Mike, do you realise the spring needs compression by more than the power of your hand?, i tried to show that
 

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The calipers I bought probably should have been scrapped as they were VERY rusty and seized but I gave it a go and they worked quite well for at least six months but may have been too far gone. Either that or I got dirt in the seal or cocked it up somehow.
Hopefully the refurbed ones I bought will be better.

And Yes the springs need to be compressed with something like a bearing puller. No way you'll ever do it with a screw driver and a pair of circlip pliers.
 

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mgf
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Great post! This is a task I plan to undertake myself in the next couple of weeks following the success I had with the front ones. I have already purchased the paint and a set of braided Goodridge hoses. It is great to be able to see the potential pitfalls in advance and buy any additional tools required.

Sounds like Big Red were a good company to deal with providing after sales advice. I bought the front kit from a generic auto factor but doubt I would have recieved any advice on installing the parts. I may pay the extra £££ and go for the Bigg Red kit for the rear.
 

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mgf
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Great post indeed!
Just a question about the caliper guiding pins:
One is smooth and one has a rubber collar.

Can anyone explain why these are different? And maybe most important : which one goes where ?

Would silicone grease be a good idea to refit these with ?

Any answer is greatly welcomed :)
 

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Incony - Excellent write up. I have a question for you - to replace the dust cover, does one have to take out the piston or can one replace it with the piston in place (ie no need to drain the brake fluid et al)? I have a damaged dust cover bit the rest of calliper is fine. I really do not want to dismantle the lot to just replace the dust cover. Thanks.
 

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mgf
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Discussion Starter #51 (Edited)
https://forums.mg-rover.org/mgf-mgtf-sponsored-mgfntfbitz-12/mgf-front-brake-caliper-refurb-811177/

i recommend one removes the piston. right now i dont have time to describe why or how,,, but you will damage the new seal if you try to do it without removing the piston...

i refurbed the front brakes recently and posted here, but the pictures i uploaded wont show this mo, because they are not on my own website, so i have to load them again to make the post that shows you how, and why... etc... i dont think i can do that before monday.. ive no time,,, i am on 12 hour shifts till sunday night..

if you have a couple of days patience .. i will have the front brake post i made, that shows you how to assemble the outer dust seal back up and running... but this mo you cant see the pics

( SORTED NOW )

sorry - its not my fault the site wont show them. but i will have it sorted asap.
 

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mgf
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Discussion Starter #52 (Edited)
http://forums.mg-rover.org/mgf-mgtf-sponsored-mgfntfbitz-12/mgf-front-brake-caliper-refurb-811177/

ive sorted most of the post now, julian.. bit more to fix,,, but i will get it all...... Here is the core of the how too .. and why i think the piston must come out to fit the new seal. and its because of the pistons tight fit... so.. you need an A1 piston and an A1 seal.. - and lube, and dexterity to do it... once you have.. it is easy... and you will realise why it must be done like i show... no rust on the piston bore, piston, and a new seal..

the piston must be new or perfect.. the bore must be fault free, the fluid in the bore must be perfect... and the two seals, inner and outer - must be undamaged etc etc


**** i hate how hard the web is to to use these days. things that took a click now need hours to get fixed.
 

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Discussion Starter #54
its done julian i did it yesterday all except one pic...

click on the link... mgf front brakes.,.
 

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I got my handbrake actuator out with a screwdriver thus ruining the circlip and found a new one in the kit. For reassembling, the compressor was easy to make, but the re insertion of the circlip needed a bush that I made on my lathe that matched the cylinder and the inner diameter of the lower reduced part. From there it was easy pushing the compressed circlip into the housing slot. I was almost about to buy new ones.
 

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Incony, thanks for this write up. I don't think I would have had the confidence to have given this refurbishment a go had it not been for this comprehensive guide. Like few people on this post I had a lot of trouble centring the hand brake return spring and its cage while also trying to compress it. I tried for two hours with a bearing puller and a standard socket. After that I decided, like Humphrey Lees, that I'd make a tool that would centre the cage and spring while also compressing it. I used a 14mm x 14mm bar just long enough to sit across the brake pad pushers on the none piston side. I then put a threaded M8 hole down the centre. I put a taper the same as an M8 drill bit on a piece of M8 threaded bar, so that it will push a bush with an M8 hole in it centrally.

I made a bush (drawing and photos attached). The piston spindle is 10mm maximum diameter so I took a 60mm long 20mm diameter round bar and put a 10mm hole down the centre 40mm deep. I then turned the same end down 15mm from the end 0.25mm at a time until the end would just fit inside the spring. On the other end I put an 8mm hole just 10mm deep. So there's 10mm between the two holes and plenty of metal to bare the pushing force between the two holes. It’s then just a matter of using the bar and M8 threaded rod to push the bush, cage and spring into the calliper. Just a word of warning: The hole in the cage is slightly bigger than the hole in the spring. So the cage does not quite centre automatically. However, since the whole thing is stable, almost centred and square it’s relatively easy to nudge the cage into the centre once it’s under light pressure by eye. I managed to get the circlip on both callipers in under 15mins with this.

Hope this helps since compressing the spring without damaging the cage is by far the hardest part of refurbishing the callipers. I've attached photos since they show it much better than I can describe.
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20200303_125646.jpg
 

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I rebuilt my calipers just be careful the 2 circlips are different I put mine together all assembled screwed the pison in and the centre pin came loose and I can't get the piston fully in or out so the caliper is scrap. The only way to get the piston out now is to cut the whole think up. Lesson learnt there!
 
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