poohbear Posted July 1, 2008 Share Posted July 1, 2008 Right, finally split the calipers and got all the pistons out. Whilst cleaning up the bores I have found some corrosion on the side of the bore. it is behind the fluid seal and can be seen by eye and felt by touch. Can anyone tell me whether this is a scrapper or is ti safe to use? Many thanks, D. Quote Link to comment Share on other sites More sharing options...
Lars L Posted July 1, 2008 Share Posted July 1, 2008 IMHO, I would get me new calipers... Quote Link to comment Share on other sites More sharing options...
Alan Broadbent Posted July 1, 2008 Share Posted July 1, 2008 Get some new ones! Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 1, 2008 Author Share Posted July 1, 2008 OK thanks guys - as I have the pistons and seals already can you buy just the calipers or do they come complete? Quote Link to comment Share on other sites More sharing options...
wkw90 Posted July 1, 2008 Share Posted July 1, 2008 You only get one chance to stop Quote Link to comment Share on other sites More sharing options...
Les Henson Posted July 1, 2008 Share Posted July 1, 2008 Dress the inside of the bores with 1000 or 1200 grade wet/dry paper - lubricated with a thin oil. Don't spend hours doing it - just a few minutes and then see what it looks like. The piston has a rubber ring, so some slight tolerance may well be ok. Les. Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 1, 2008 Author Share Posted July 1, 2008 Thanks Les - have just spent the evening doing as you suggested - the bores have come up a treat. I'll pop a caliper in to my local garage tomorrow to see what their concensus is. wkw90 - good point! Quote Link to comment Share on other sites More sharing options...
Les Henson Posted July 1, 2008 Share Posted July 1, 2008 If you are going to take a chance on using the calipers, then put them back on the vehicle, bleed the system, then stamp on the brakes and maintain the pressure for a minute or so. This will simulate emergency braking. If it's going to leak - it will do so while you do this test. Les. Quote Link to comment Share on other sites More sharing options...
BLACK CAB Posted July 1, 2008 Share Posted July 1, 2008 The fluid seals inside dia when fitted is considerably smaller than the bore dia of the caliper body. The plain caliper piston is in fact floating within the bore and so will most likely be fine..... rebuilding brake components requires a clean environment and reasonable care.... .....as with all these critical type components. I would clean up the bores, check for corrosion in the piston seal rebates and if good wash them out with brake cleaner before rebuild them. Ensure you soak seals in clean fluid during the rebuild. But if your not 100% happy with what you have, buy new AP Lockheed parts. Rod Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 2, 2008 Author Share Posted July 2, 2008 spent hours cleaning the calipers up - spent minutes wrecking three seal kits will be sourcing new calipers and be done with it methinks. thanks for the help guys - getting a little bolder by the day thanks to all the peeps here D. Quote Link to comment Share on other sites More sharing options...
JST Posted July 2, 2008 Share Posted July 2, 2008 put the first seal in then the piston so you can use the piston as a guide for the outerwipe seal and the dust cover or use a socket with lever to push them in evenly alround Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted July 2, 2008 Share Posted July 2, 2008 The seal is made between the circumferential surface of the seal-groove, the sealing ring and the piston - the bore itself has nothing to do with sealing - only keeping the piston straight. As mentioned above, the important bit on the caliper is that there is no rust or pitting within the groove. The piston is the really important bit since it is the part that has to slide and seal (although it doesn't actually slide often) and so must be immaculately smooth and clean. (This is why I dislike the design of the outer (dirt) seal on these calipers - others I have seen have a bellows arrangement meaning that when a piston extends to take up brake wear it stays clean so that when you push it back in when replacing the pads,you don't wreck the seal...) sorry if this is rambling - blame is on the Stella Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 3, 2008 Author Share Posted July 3, 2008 Thanks JST - have had chance to calm down, have ordered more seal kits (3 of!!) and will try again over the weekend. Threesheds - My thoughts exactly, the Haynes just seemed to be really specific that the bores were perfectly smooth. Anybody else got any clever ways of trying to get the retaining rings in square - what size socket would you recommend as a drift? Lastly, could the fact that the old retaining rings were missing mean that the seats have been damaged by exposure to road dirt and the like over the years? The first two went in OK with me only bending two rings (I put htis down to lack of experience with the first two!) but I just could not get the others in square however I tried. Once again - thanks peeps! Quote Link to comment Share on other sites More sharing options...
paintman Posted July 3, 2008 Share Posted July 3, 2008 They might be missing because somebody else has done the job before & found them - like the rest of us - to be a real PITA You might find a gentle chamfering of the edge of the ring will help. Quote Link to comment Share on other sites More sharing options...
jcwcooper Posted July 3, 2008 Share Posted July 3, 2008 as above give the groove where the retainer sits a scrape with a screwdriver gently to remove and mud and rust thats built up and a light sand be carefull not to damage it at all. I broke about 4 retainers doing my front calipers Dave. Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 3, 2008 Author Share Posted July 3, 2008 jcwcooper - It's comforting to know I'm not on my own. Will try and clean up the groove tonight - new seals should be here in the morning. Many thanks, D. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted July 3, 2008 Share Posted July 3, 2008 The retaining rings are very difficult to get in. I always buy two sets because of this. Les. Quote Link to comment Share on other sites More sharing options...
BLACK CAB Posted July 3, 2008 Share Posted July 3, 2008 I have done quite a few caliper rebuilds and this is how I do it. Make sure the grooves for both the piston fluid seal and the wiper seal are completely clean, use a small bent-up flat bladed screw driver to scrap them. Dunk all the seals in clean fluid and fit the first piston seal in its groove, then partly insert the piston ensuring it is square to the bore. Install the wiper seal in to the retainer and then slid down over the protruding skirt of the piston, ensuring that it is in contact with the caliper body around its entire circumference. Now find a suitable piece of steel (a cleaned off back plate from a brake pad is ideal, turn it through 90 deg's so that it dose not catch the caliper body) rest this across the piston skirt and most importantly make sure it covers all of the wiper seal retainer. Slowly squeeze using a G-cramp or similar until the piston is completely flush with the body, with a certain amount of luck the retainer will have seated square. If you get one that is a problem install the remaining piston or pistons if you have not split the caliper body halves. Then clamping the good one/s, partly blow out the problem piston and try again. Normally I have no problem using this technique. Oh and use Genuine AP seal kits. Rod Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 3, 2008 Author Share Posted July 3, 2008 Doh - why didn't I think of that in the first place Any idea if the seal kits paddocks supply are the AP ones? Thats where the new ones are coming from Quote Link to comment Share on other sites More sharing options...
BLACK CAB Posted July 4, 2008 Share Posted July 4, 2008 No the Paddock's ones are total rubbish. The seals are just not right and have flashing, the wiper seal retainers are also poorly formed. This makes them very difficult to fit, ask me how I know . Make sure there genuine AP Lockheed. Rod Edit. to say return them and buy from main dealer or BearMach. Quote Link to comment Share on other sites More sharing options...
poohbear Posted July 5, 2008 Author Share Posted July 5, 2008 Thanks Rod, unfortunately didn't read your post until after I fitted them Still thanks to the help here the second attempt at fitting went remarkably well. I did as you suggested and it went a dream with me only wrecking 2 retaining rings - It's comforting to know that it isn't just me being totally inept though if the quality is as bad as you say. End result is quite pleasing - though i did wreck a new set of pads due to contamination, mental note to self to check the bleed nipples before pressurising system next time Anyway - many thanks to all on the forum - I feel I have climbed another peg on the amazingly steep learning curve I appear to have leapt on. Now onto the next job (see swivel ball post ) Dave. Quote Link to comment Share on other sites More sharing options...
DaveSIIA Posted July 5, 2008 Share Posted July 5, 2008 - though i did wreck a new set of pads due to contamination, mental note to self to check the bleed nipples before pressurising system next time Brake fluid on the pads isn't a problem. Brake fluid is water soluble, so just remove the pads in warm soapy water and dry. Oil is a different matter all together. Quote Link to comment Share on other sites More sharing options...
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