31-03-2016, 02:25 PM
(This post was last modified: 31-03-2016, 02:28 PM by pug306driver.)
I had this problem new year as flexy hoses needed renewing.
I wire brushed the rear nipples and applied penetrant over many days, also cleaned out the nipple "hole" all the way to the bottom ( double diameters, cant remember sizes ) , fitted some washer tube and filled that with penetrant also, The penetrant ( carlube graphite stuff in small grey plastic bottle ) was left to do its stuff over many days whilst I sorted the fronts.
heat gun and hey presto the rears came out no problems, but the fronts grrrrrrrrrrrrr.
The flexy hoses came out of the calipers ( bosch ) no problem, the 2564766=$%£"**&%$ nipples!! different story!
The calipers where gunna be stripped anyways for new seals, so they where removed and stripped.
The sheared nipple, the one that sheared clean off, I used the MIG method. I welded a blob to the wire brushed and bright remains. Be careful as you don not want to weld the nipple remains to the caliper, risky but possible, even on alloy ( bike ) calipers.
I welded a blob to the blob, and repeated. I ground an 8mm longish bolt to a taper point and welded this to the blobs.
Some heat and hey presto, it turned, lubed lubed and lubed, back and forth gentle turning and the %$£&^%$£ came out all ok, leaving the caliper thread all good.
The other front caliper was stripped, heated as much as I dare, and the nipple came out ok when the caliper was cooling down. Thank you god!!!
Drilling out a sheared nipple, mangled screw, seized bolt etc would be a final last lasrt last resort for me, as I know the mig method works, even on alloy stuff.
On alloy stuff, I reckon the "thermal shock" aids the offending item removal, some p[ati9ence and gentle turning, lubing etc and they come out. If the blobs "shear off" just re blob and try again.
MY mig is 25 years old ish, a Clarke blue one using pub gas and 0.6mm wire. Its a hobby type machine 100 amp from memory.
I have used this method more or less since I purchased the mig, using oxy/acetylene and a no.1 tip prior, usually with alloy stuff sitting in water.
I wire brushed the rear nipples and applied penetrant over many days, also cleaned out the nipple "hole" all the way to the bottom ( double diameters, cant remember sizes ) , fitted some washer tube and filled that with penetrant also, The penetrant ( carlube graphite stuff in small grey plastic bottle ) was left to do its stuff over many days whilst I sorted the fronts.
heat gun and hey presto the rears came out no problems, but the fronts grrrrrrrrrrrrr.
The flexy hoses came out of the calipers ( bosch ) no problem, the 2564766=$%£"**&%$ nipples!! different story!
The calipers where gunna be stripped anyways for new seals, so they where removed and stripped.
The sheared nipple, the one that sheared clean off, I used the MIG method. I welded a blob to the wire brushed and bright remains. Be careful as you don not want to weld the nipple remains to the caliper, risky but possible, even on alloy ( bike ) calipers.
I welded a blob to the blob, and repeated. I ground an 8mm longish bolt to a taper point and welded this to the blobs.
Some heat and hey presto, it turned, lubed lubed and lubed, back and forth gentle turning and the %$£&^%$£ came out all ok, leaving the caliper thread all good.
The other front caliper was stripped, heated as much as I dare, and the nipple came out ok when the caliper was cooling down. Thank you god!!!
Drilling out a sheared nipple, mangled screw, seized bolt etc would be a final last lasrt last resort for me, as I know the mig method works, even on alloy stuff.
On alloy stuff, I reckon the "thermal shock" aids the offending item removal, some p[ati9ence and gentle turning, lubing etc and they come out. If the blobs "shear off" just re blob and try again.
MY mig is 25 years old ish, a Clarke blue one using pub gas and 0.6mm wire. Its a hobby type machine 100 amp from memory.
I have used this method more or less since I purchased the mig, using oxy/acetylene and a no.1 tip prior, usually with alloy stuff sitting in water.