Strictly speaking, It's not the 'loctite' factor. Caliper mounting bolts are usually one-use stretch bolts that shouldn't be re-used. Correctly torqued bolts shouldn't need threadlock.
Front brake disc Torque Wrench settings.
- Thread starter Brownster
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Good point, I've got the Haynes as well but when I came to sort my fronts out I was informed by a local spares place that the mounting bolts were SEAT parts only as they came pre-treated with loctite, maybe some confusion between the front and rear application as you mentioned...
DPJ wrote
Strictly speaking, It's not the 'loctite' factor. Caliper mounting bolts are usually one-use stretch bolts that shouldn't be re-used. Correctly torqued bolts shouldn't need threadlock.
Elsawin describes them as "self-locking", a description that makes more sense if applied to a threadlock coating rather than a bolt which is stretched beyond its elastic limit by assembly.
All torque settings are about applying a pre-determined amount of stretch to the assembly, bolt or stud. Stretch bolts appear to be used in automated car assembly to give a wider degree of latitude to the safe fastening range - x number of turns rather than a precise torque.
I've been told by VW technicians that the bolts on the Girling calipers on my old Golfs were attached with pre-coated bolts and that it was as effective to use the old bolts with loctite when doing DIY pad replacement. I believe it's the same for the rear caliper bolts on the Leon/Toledo. The front caliper attachment bolts are not specified for replacement if disturbed, according to ElsaWin.
Strictly speaking, It's not the 'loctite' factor. Caliper mounting bolts are usually one-use stretch bolts that shouldn't be re-used. Correctly torqued bolts shouldn't need threadlock.
Elsawin describes them as "self-locking", a description that makes more sense if applied to a threadlock coating rather than a bolt which is stretched beyond its elastic limit by assembly.
All torque settings are about applying a pre-determined amount of stretch to the assembly, bolt or stud. Stretch bolts appear to be used in automated car assembly to give a wider degree of latitude to the safe fastening range - x number of turns rather than a precise torque.
I've been told by VW technicians that the bolts on the Girling calipers on my old Golfs were attached with pre-coated bolts and that it was as effective to use the old bolts with loctite when doing DIY pad replacement. I believe it's the same for the rear caliper bolts on the Leon/Toledo. The front caliper attachment bolts are not specified for replacement if disturbed, according to ElsaWin.
The actual retaining screw is 15mm long as I mentioned earlier in post #9, the tap doesn't replace the screw, it just re-cuts the thread in the hub which almost inevitably gets spoiled trying to remove the old retaining screw.
Yesterday I spoke to the local Seat dealer and he said they wouldn't usually replace the bolts unless faulty, especially as they are quite pricey to replace, and he just advised me to Loctite them.
Ste
that's because the dealer is wrong.... they're not that dear at all, and you don't want your brakes coming loose
dealers are NOT the fountain of all knowledge by a long shot
dealers are NOT the fountain of all knowledge by a long shot
Yep, some dealer practices are poor. First time I bought front caliper mounting bolts from dealer, they had never been ordered on their system before......!
Mine didn't have any threadlock residue on when I removed them which I would expect to see if it was used.
However Vagcat.com refers to the bolts as "N 90708502 Self-locking bolt M12X1,5X35" which suggests they are stretch bolts or use an alternative means of mechanical thread locking (although the only alternatives I know of are thread locking inserts, which I doubt would be used in this instance, or tie-wiring, can definately rule this one out).
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ElsaWin's Seat data doesn't say anything about replacing the front mounting bolts either, only the rear ones.
Right all sorted now thanks for your advice.
Once last question - when i wound my calipers back in I didnt take the cap off the master cylinder, once done i noticed that there was a little pool of fluid on the floor. Looking at the cylinder head it looks to have leaked from there! however if it didnt how soon could i tell when pressing the brakes - i dont wanna be driving along the road and realise that there is a leak in the system that i have caused, and have no brakes!!!
what are the chances of it bursting a pipe in the system? am i being paranoid!?
Cheers
Ste
Once last question - when i wound my calipers back in I didnt take the cap off the master cylinder, once done i noticed that there was a little pool of fluid on the floor. Looking at the cylinder head it looks to have leaked from there! however if it didnt how soon could i tell when pressing the brakes - i dont wanna be driving along the road and realise that there is a leak in the system that i have caused, and have no brakes!!!
what are the chances of it bursting a pipe in the system? am i being paranoid!?
Cheers
Ste
Your master cylinder won't have been filled to the brim, so you'll mainly have been compressing the air in it when you wound back the pistons. You're unlike ly to have burst anything, certainly not a pipe. Clear up the mess and don't do it again!
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