If you've been following the saga of Becky (our new/old Panda which we bought earlier this year) you'll know that I'm slowly working my way through her from front to rear assessing and rectifying things as I go. The big job so far has been the timing belt which I've just completed, but there were a few days when I couldn't work on that as I was waiting for parts. Her front end was up in the air anyway so checking out the front brakes and suspension/steering whilst waiting on the delivery seemed logical.
When we test drove Becky at the garage the brakes generally were very noisy, as in "rusty discs". The sales man spun us a line about them cleaning up with driving and, that is true as long as it's only light surface rust, but these were very noisy! Hmmm! The garage agreed to let me put her up on a ramp so I was able to see that the discs were rusty but in a "strange" sort of way - more later. The car had been in stock for some time and had been reduced in price by a large amount (I'd been watching it for a while on the computer) and the under body looked really good. New sump, bottom suspension arms and a few other parts too. Rear beam and spring pans not too bad either. Tried to negotiate the price on what was already a really good price but, not surprisingly, they wouldn't come any lower. Here are a couple of underneath shots.
Well, having looked at a couple which were far worse we decided Becky was the one for us so we bought her. The garage spruced her up a bit and had obviously driven her around a bit with his foot on the brake because they were much quieter when we drove her away - but not silent!
So here I am now sitting on the ground by the NSF wheel hub - the wheel is already off - looking at a disc which from the outside looks remarkably new, pads look new too, back side of disc looks horrid! Ok lets get the disc off, should be easy as the pads and discs have obviously not seen much running so must have been stripped down recently. But no! The first thing I notice is there is a rusty, mangled, split pin in the hole where the R clip should be. Someone has tried to get it out and broken bits of it off. The retaining pin itself is not going to come out unless this split pin is dealt with - my small sharp chisel soon sees to that! OK the pin should just tap out now. Not a chance, it's rusted solidly in place! A rather more enthusiastic tap on the end just goes to prove it's rusted solid and starts to mushroom the end of the pin! Any more enthusiastic application of the hammer is certainly going to turn the pin into a rivet head thus rendering it's removal even more difficult but also heavy hitting is liable to snap off one, or both, of the lugs on the bottom of the caliper carrier and then I've got real problems! This, my local garage tells me is very common. What to do now? Well I could drill the pin out but if I snap the drill bit it's going to make more work. so I decide to try to loosen it (time not being a factor). Over the years I've found Plus Gas is really unbeatable as a releasing agent so I gave the pin a good spray with it. An American friend would dispute that though as he prefers PB Blaster?
Then give it some smart taps all over, not real hits just vigorous taps. the idea is to introduce shock and vibration into the work so that the rust is cracked and disturbed thus allowing the release fluid to penetrate. I did this for about 4 or 5 minutes giving it a little extra squirt of fluid from time to time. I didn't think to take pictures as I was doing this so I later, after getting the pin out, reinstalled it and took the following images
My first attempt at this didn't free it so i sprayed more fluid on it and left it overnight. Repeated the process in the morning and almost immediately the pin moved and then, quite easily really, slid out.
Had this failed I would escalate to the next level with heat, cold and release oil. Here are pics of my weapons of choice.
You need to be careful with the blowtorch and I only resort to it in the most extreme cases as it can damage seals, rubber gators, bushings, etc. The idea is that you are going to expand the metal with the torch (you don't need to get it stinking red hot) then cool it rapidly with the freezer spray, which also contains a releasing oil. The heating followed by rapid cooling hopefully cracks up the rust and lets the releasing agent penetrate. The spray is quite expensive because you need to spray it continuously for about 20 seconds or so (depends on how thick the metal is) to get the full freezing effect. a short squirt is not going to get the job done. I find about a third to half a can is used for each attempt. But, boy does it work if you use it right!
In this case though I got it freed up with just the Plus Gas and tapping method (and boy was it rusted solid - wish I'd thought to do a picture). Now for one of the surprises. The pin is out and the bottom of the caliper is free. I gripped the caliper and gave it a wee wiggle to free it up on the pads. It all seemed to be nice and free so I tried to swing the caliper up on the top pin. It only moved about a half inch before stopping suddenly! Never had this before, what's going on? Well have a look at the back of this pad (took a pic after I got it in pieces)
The anti-squeal shim is riveted to the back of the pad and the rivet heads are standing proud. This was catching on the inside of the caliper piston. Forcing the piston just a little further into its bore solved the problem and let me swivel the caliper up. I haven't seen a pad with these rivets before so that's another one to remember.
All this was a bit strange because the pads looked as good as new.
So someone must have very recently had this all in pieces so how come the rusted up pins? Oh well, lets get the discs off and see what they look like. Another surprise coming up here. Oh! the carrier retaining bolts are not very tight at all and undo easily! So that's how they did it, took the entire caliper and carrier off as one unit, probably after mangling that split pin and finding they couldn't get the retaining pin out!
Bare disc now, just those little pointy screws to undo and they come out real easy. The disc tries to fall off the hub on its own, again wasn't expecting that, it's not unusual to have to whack it with my big soft face hammer to get it off, but I can see now that the disc looks almost new on the outside with the factory anti corrosion finish still in place. Turn it over and Oh deary me, there's the cause of all the noise.
This looks terminal, new disc needed I think! Still, nothing to loose, lets try cleaning it up. So I got my trusty old drill out with a well used (so not aggressive) abrasive disc in it and gently ground away all the rust. To my absolute astonishment it cleaned up beautifully!
But how is it for thickness? Got my micrometer out and it measures 0.430" all the way round (so same thickness all the way round). In new "money" my conversion chart says that 0.4375" equals 11.125mm and a new disc has an acceptable tolerance of between 10.8 to 11.1mm (according to Mr Haynes) so the disc is spot on! I would not believe this could happen if I saw it in a fairy tale! What's even more astonishing is that the other side (OSF) was exactly, and I mean EXACTLY the same, in every respect except that it had the mangled remains of an R clip in it's bottom retaining pin!
Bought a pad fitting set, about £8.00 from my local factor, to get new pins. built the whole thing back together with a light smear of copper grease on the hub to stop the disc seizing on, Cera Tec ceramic grease sparingly applied to the back of the pads and carrier where the pads fit and a little more copper grease around the new retaining pins. so ended up with this
Quite pleased really. It could have all turned out quite expensive but with a little patience and the right gear it all came good. The other side went back together just as satisfactorily. The car drives beautifully with silky smooth brakes! All that's left now to do is the rears which I know have slight fluid weeps on the cylinders so they will be getting renewed.
Just to finish up with, thought you might like a shot of my little "army" of helpers in the war against corrosion and seized up parts and fixings. The Ceramic grease, on the left in the white tub, is especially good on things that get very hot like exhaust down pipes, manifold bolts, etc. the greasy component burns away but leaves the ceramic part behind to protect.
Well, I think that's it for this time. I wouldn't like to bet the rear cylinders come off easily. Could be an excuse for doing something on making metal brake pipes? The end of the tunnel is in sight chaps! Now if only that fault code about the torque sensor on the electric steering doesn't come back!
Cheers to all
Jock
When we test drove Becky at the garage the brakes generally were very noisy, as in "rusty discs". The sales man spun us a line about them cleaning up with driving and, that is true as long as it's only light surface rust, but these were very noisy! Hmmm! The garage agreed to let me put her up on a ramp so I was able to see that the discs were rusty but in a "strange" sort of way - more later. The car had been in stock for some time and had been reduced in price by a large amount (I'd been watching it for a while on the computer) and the under body looked really good. New sump, bottom suspension arms and a few other parts too. Rear beam and spring pans not too bad either. Tried to negotiate the price on what was already a really good price but, not surprisingly, they wouldn't come any lower. Here are a couple of underneath shots.
Well, having looked at a couple which were far worse we decided Becky was the one for us so we bought her. The garage spruced her up a bit and had obviously driven her around a bit with his foot on the brake because they were much quieter when we drove her away - but not silent!
So here I am now sitting on the ground by the NSF wheel hub - the wheel is already off - looking at a disc which from the outside looks remarkably new, pads look new too, back side of disc looks horrid! Ok lets get the disc off, should be easy as the pads and discs have obviously not seen much running so must have been stripped down recently. But no! The first thing I notice is there is a rusty, mangled, split pin in the hole where the R clip should be. Someone has tried to get it out and broken bits of it off. The retaining pin itself is not going to come out unless this split pin is dealt with - my small sharp chisel soon sees to that! OK the pin should just tap out now. Not a chance, it's rusted solidly in place! A rather more enthusiastic tap on the end just goes to prove it's rusted solid and starts to mushroom the end of the pin! Any more enthusiastic application of the hammer is certainly going to turn the pin into a rivet head thus rendering it's removal even more difficult but also heavy hitting is liable to snap off one, or both, of the lugs on the bottom of the caliper carrier and then I've got real problems! This, my local garage tells me is very common. What to do now? Well I could drill the pin out but if I snap the drill bit it's going to make more work. so I decide to try to loosen it (time not being a factor). Over the years I've found Plus Gas is really unbeatable as a releasing agent so I gave the pin a good spray with it. An American friend would dispute that though as he prefers PB Blaster?
Then give it some smart taps all over, not real hits just vigorous taps. the idea is to introduce shock and vibration into the work so that the rust is cracked and disturbed thus allowing the release fluid to penetrate. I did this for about 4 or 5 minutes giving it a little extra squirt of fluid from time to time. I didn't think to take pictures as I was doing this so I later, after getting the pin out, reinstalled it and took the following images
My first attempt at this didn't free it so i sprayed more fluid on it and left it overnight. Repeated the process in the morning and almost immediately the pin moved and then, quite easily really, slid out.
Had this failed I would escalate to the next level with heat, cold and release oil. Here are pics of my weapons of choice.
You need to be careful with the blowtorch and I only resort to it in the most extreme cases as it can damage seals, rubber gators, bushings, etc. The idea is that you are going to expand the metal with the torch (you don't need to get it stinking red hot) then cool it rapidly with the freezer spray, which also contains a releasing oil. The heating followed by rapid cooling hopefully cracks up the rust and lets the releasing agent penetrate. The spray is quite expensive because you need to spray it continuously for about 20 seconds or so (depends on how thick the metal is) to get the full freezing effect. a short squirt is not going to get the job done. I find about a third to half a can is used for each attempt. But, boy does it work if you use it right!
In this case though I got it freed up with just the Plus Gas and tapping method (and boy was it rusted solid - wish I'd thought to do a picture). Now for one of the surprises. The pin is out and the bottom of the caliper is free. I gripped the caliper and gave it a wee wiggle to free it up on the pads. It all seemed to be nice and free so I tried to swing the caliper up on the top pin. It only moved about a half inch before stopping suddenly! Never had this before, what's going on? Well have a look at the back of this pad (took a pic after I got it in pieces)
The anti-squeal shim is riveted to the back of the pad and the rivet heads are standing proud. This was catching on the inside of the caliper piston. Forcing the piston just a little further into its bore solved the problem and let me swivel the caliper up. I haven't seen a pad with these rivets before so that's another one to remember.
All this was a bit strange because the pads looked as good as new.
So someone must have very recently had this all in pieces so how come the rusted up pins? Oh well, lets get the discs off and see what they look like. Another surprise coming up here. Oh! the carrier retaining bolts are not very tight at all and undo easily! So that's how they did it, took the entire caliper and carrier off as one unit, probably after mangling that split pin and finding they couldn't get the retaining pin out!
Bare disc now, just those little pointy screws to undo and they come out real easy. The disc tries to fall off the hub on its own, again wasn't expecting that, it's not unusual to have to whack it with my big soft face hammer to get it off, but I can see now that the disc looks almost new on the outside with the factory anti corrosion finish still in place. Turn it over and Oh deary me, there's the cause of all the noise.
This looks terminal, new disc needed I think! Still, nothing to loose, lets try cleaning it up. So I got my trusty old drill out with a well used (so not aggressive) abrasive disc in it and gently ground away all the rust. To my absolute astonishment it cleaned up beautifully!
But how is it for thickness? Got my micrometer out and it measures 0.430" all the way round (so same thickness all the way round). In new "money" my conversion chart says that 0.4375" equals 11.125mm and a new disc has an acceptable tolerance of between 10.8 to 11.1mm (according to Mr Haynes) so the disc is spot on! I would not believe this could happen if I saw it in a fairy tale! What's even more astonishing is that the other side (OSF) was exactly, and I mean EXACTLY the same, in every respect except that it had the mangled remains of an R clip in it's bottom retaining pin!
Bought a pad fitting set, about £8.00 from my local factor, to get new pins. built the whole thing back together with a light smear of copper grease on the hub to stop the disc seizing on, Cera Tec ceramic grease sparingly applied to the back of the pads and carrier where the pads fit and a little more copper grease around the new retaining pins. so ended up with this
Quite pleased really. It could have all turned out quite expensive but with a little patience and the right gear it all came good. The other side went back together just as satisfactorily. The car drives beautifully with silky smooth brakes! All that's left now to do is the rears which I know have slight fluid weeps on the cylinders so they will be getting renewed.
Just to finish up with, thought you might like a shot of my little "army" of helpers in the war against corrosion and seized up parts and fixings. The Ceramic grease, on the left in the white tub, is especially good on things that get very hot like exhaust down pipes, manifold bolts, etc. the greasy component burns away but leaves the ceramic part behind to protect.
Well, I think that's it for this time. I wouldn't like to bet the rear cylinders come off easily. Could be an excuse for doing something on making metal brake pipes? The end of the tunnel is in sight chaps! Now if only that fault code about the torque sensor on the electric steering doesn't come back!
Cheers to all
Jock
Last edited:
