ahhrrgghh
Disaster
I spoke to soon..something has gone wrong.. help really needed .. I wish I had learnt more about C5 calipers but alas I haven't
Chaps, took the car to retest earlier.. about 15 miles away.. the handbrakes scraped through.. they actually passed but as usual the drivers side was substantially lower than the passenger side.. so all the pads and discs haven't really helped..
during the test, using the 'full handbrake application' (my idea) the nearside caliper locked on..the car then failed on that.. the car moved about 1/2 a mile and I quit with a very hot disc.. I waited an hour and moved her to a public car park and that was that.. she's stuck there
what on earth haven't I done? should I have done? can I do now?
I followed this guide mostly (but I didn't bother to let the bleed off before winding the piston back clockwise - which was very easy to do) and I didn't bleed the brakes afterwards.. I don't know why I didn't to be honest..
•If doing this on the ground, chock the front wheels front and rear sides
•Suspension in lowest setting
•Gearbox in Park
•Set the auto park brake feature to OFF. With ignition on, push the left roller in the steering wheel pad, go to vehicle parameters, scroll to auto park brake, push roller to change to un ticked, then scroll to OK and push.
•Foot on brake, push park brake "lever" so that park brake dis-engages (whirr from under car). Park brake should now be off. Turn off ignition.
•I did not disconnect the battery. You may choose to do so
•Remove key from barrel. Idiot proofing feature
•Loosen rear wheels studs ready for removal and jack one side of car and remove wheel. Use extender stud to make life easier.
•Remove park brake cable from its connector at the base of the calliper then withdraw including its plastic guide. Take note of how and where the rectangular guide around the cable attaches
•Remove brake calliper studs using Torx T55 bit and lots of strength or a percussive persuader against the bar - you need to "crack" the Loctite used to hold the studs in. It’s a bit of a fiddle to get the tools in the right place and be careful of the brake hose when doing the top stud. To me it looks to easy to damage if you slipped in enthusiasm.
•If your discs and pads are very worn you may need to completely remove the disc and calliper together. It should be about a T27 torx to remove the two screws in the disc
•As mine were well worn I had to do the previous step and also decided to remove the brake pipe. 11mm spanner. Have a suitable pipe and vessel ready to collect dribbling brake fluid
•Once the disc and calliper were off I had to gently press the calliper back against a padded hard surface to get the remaining fluid out so that the calliper would open enough to remove the disk and then pads.
•As I later found it also makes refitting easier if you remove the tension spring that is attached to the park brake lever arm after removing the calliper.
•Remove the anti rattle spring from the front face of the calliper
•Remove the outer and inner old pads – there is a small tension spring attached to the the calliper edge of the inner pad. Use a little force and the whole pad and spring will come out.
•Using a suitable piston wind back tool, wind the piston back in – clockwise both sides. This works much faster without the park brake lever tension spring in place as I found on the second side I did.
•Clean the calliper as much as you wish with a suitable product.
•Grease the slides of the calliper with a suitable grease.
•Fit new disk and marvel at how clean and shiny it is (no pics taken! D’Oh!!)
•Place new inner pad in calliper then new outer.
•Ensure calliper is fully relaxed and then fit over the disc edge and guide into place using one of the calliper studs as a temporary holder
•Put a small amount of Loctite on the other stud and fit to finger tightness.
•Remove the holder stud and Loctite and refit to finger tightness
•Tighten both studs using a bar and tool
•Refit brake hose if you have removed it
•Reconnect the tension spring to the park brake lever if you removed it.
•Reconnect park brake cable ensuring you reconnect the guide on the outer of the cable
•At this time I had to refit this side wheel then do the same procedure on the other side as I did not have the car on stands to hold the whole rear of the car up. If you’re doing this on a hoist or with the rear completely on stands then proceed to do the whole procedure on the other side of the vehicle
•After completing the second side and you have double checked that all connections are in place – brake lines, park brake cable, park brake tension spring – then proceed to the normal process of bleeding the rear brakes - this may be with a brake bleeding device or with an assistant starting the car and activating the brakes to your instructions.
•Once you are confident the brakes are bled properly, have the assistant manually activate the park brake. Then turn the park brake off. If all looks ok, then activate the park brake again and get the assistant to hold the lever for a few seconds for Maximum Tightening of Park Brake and the resultant “Boing” sound from the console.
•All should be OK
•Refit wheels, lower car and tension studs.
•If you usually use the auto park brake feature ensure you reactivate it through the vehicle’s menu as you are used to it working and don’t want to return to the car one day and not find it….
•Take for a careful drive to check the kwalitee of yaw werk.
I don't really understand what goes on in a C5 caliper.. eg the wind back, an idiots guide to the units would be good..even older c5's
I have read something about older c5's where you are supposed to somehow set the piston out so the pads are nearly touching the disk.. what why how?
