Brake Caliper Pistons
Discussion
Sorry if this is in the wrong place...
I'm fitting some new (old) brake calipers to my car. The boots around the pistons are all crinkled so I'm going to replace them with new while it's easy to do so - should I take out the pistons and seals as well in case dirt has gotten in, give it a clean in there and replace the seals, or is that not necessary?
I'm fitting some new (old) brake calipers to my car. The boots around the pistons are all crinkled so I'm going to replace them with new while it's easy to do so - should I take out the pistons and seals as well in case dirt has gotten in, give it a clean in there and replace the seals, or is that not necessary?
If you have the luxury of time and the brakes are an unknown quantity, I’d say it’s worth pulling the pistons and replacing the internal seals before you do the dust seals.
If they are known good and working though, I’d probably leave them alone given how much fun it can be extracting pistons from callipers!
If they are known good and working though, I’d probably leave them alone given how much fun it can be extracting pistons from callipers!
Appreciate the replies. The calipers aren't a known quantity, but they were sold as being "in good working order" for what that's worth. All threads are in excellent condition as described and I'm not sure whether the crinkling would actually be a problem or would allow any dirt in. I've read that it can be caused by pushing the pistons too far in, so perhaps I did it when removing the old pads that came attached.
I don't have compressed air or anything similar that would make removing the pistons easy, but it might be obvious whether any dirt has gotten in there once I remove the boots, so perhaps that's the next step.
Nothing exotic, it's a Skoda Yeti, but I'm fitting Porsche 986 calipers and half the point is to do the work myself and learn a bit in the process. The new boots (they come with seals as well) are easy to find and cheap, and already ordered.
I don't have compressed air or anything similar that would make removing the pistons easy, but it might be obvious whether any dirt has gotten in there once I remove the boots, so perhaps that's the next step.
Nothing exotic, it's a Skoda Yeti, but I'm fitting Porsche 986 calipers and half the point is to do the work myself and learn a bit in the process. The new boots (they come with seals as well) are easy to find and cheap, and already ordered.
Edited by Tiglon on Sunday 18th May 15:28
Panamax said:
Do those calipers actually fit a Skoda Yeti? I'm thinking both installation and then clearance for the wheel.
Your insurers will probably be interested to hear about modification of the braking system with second-hand parts from a different type of car.
They do indeed fit, it was a common modification on VAG cars, with an off the shelf adaptor. The 986 was available with 16" wheels and the Yeti has 19" McLaren wheels. They aren't huge brakes.Your insurers will probably be interested to hear about modification of the braking system with second-hand parts from a different type of car.
I'm not sure whether my insurer was particularly interested... but they have been informed.
Depending on the number of pistons, it’s worth pointing out that you want them all out together if more than one. Otherwise you’re left with one out and no pressure (not that I’ve made this mistake you understand… 
)
Different thicknesses of wooden wedge work well if there’s more than one piston for getting them level, it also identifies if one is sticking more than another.
You can get piston pliers to grip the insides rather than risk damaging/marking the sections of the piston that will have to slide past your new seals and tear them up.
A pick, brake cleaner and emery paper are good for removing any corrosion/salt that may be in there.
Good luck and hope it goes smoothly.
)Different thicknesses of wooden wedge work well if there’s more than one piston for getting them level, it also identifies if one is sticking more than another.
You can get piston pliers to grip the insides rather than risk damaging/marking the sections of the piston that will have to slide past your new seals and tear them up.
A pick, brake cleaner and emery paper are good for removing any corrosion/salt that may be in there.
Good luck and hope it goes smoothly.
darkyoung1000 said:
Depending on the number of pistons, it’s worth pointing out that you want them all out together if more than one. Otherwise you’re left with one out and no pressure (not that I’ve made this mistake you understand… )
Different thicknesses of wooden wedge work well if there’s more than one piston for getting them level, it also identifies if one is sticking more than another.
You can get piston pliers to grip the insides rather than risk damaging/marking the sections of the piston that will have to slide past your new seals and tear them up.
A pick, brake cleaner and emery paper are good for removing any corrosion/salt that may be in there.
Good luck and hope it goes smoothly.
Thank you, that's very helpful! )Different thicknesses of wooden wedge work well if there’s more than one piston for getting them level, it also identifies if one is sticking more than another.
You can get piston pliers to grip the insides rather than risk damaging/marking the sections of the piston that will have to slide past your new seals and tear them up.
A pick, brake cleaner and emery paper are good for removing any corrosion/salt that may be in there.
Good luck and hope it goes smoothly.
donkmeister said:
As they are expensive but of somewhat unknown condition I'd recommend engaging the services of Bigg Red brakes for a refurbishment.
They've done a cracking job on the calipers I've sent them. Plus you can get them finished in whatever colour anodising or powder coating you like.
Thanks for the suggestion. They're not really very expensive though and I'd rather do the work myself, it's a fun project for the sake of doing the project. They've done a cracking job on the calipers I've sent them. Plus you can get them finished in whatever colour anodising or powder coating you like.
I've already stripped them (apart from the pistons), cleaned them and painted them - not powder coating, but for a 2011 Yeti that does 20k miles a year and probably has 5 years of life remaining, that'll do. It's just a case of replacing the boots and deciding whether to replace/clean the pistons and seals as well.
Tiglon said:
... 20k miles a year and probably has 5 years of life remaining. It's just a case of replacing the boots and deciding whether to replace/clean the pistons and seals as well.
You're looking at 100,000 miles there. Well worth doing the job properly even if there's a bit more cost involved.Panamax said:
Tiglon said:
... 20k miles a year and probably has 5 years of life remaining. It's just a case of replacing the boots and deciding whether to replace/clean the pistons and seals as well.
You're looking at 100,000 miles there. Well worth doing the job properly even if there's a bit more cost involved.No I totally understand, most jobs I do on my own cars because 1) I like to learn how to do it 2) I take pride that I did it 3) I can take my time and (hopefully!) knows it's done right and 4) I can look out for other things while I'm working.
I've actually got new pistons, seals and boots to go into my daily driver at some point, as I spotted a slight tear on one of the dust boots when I did the pads and discs. My plan is to finally refurb a pair of calipers by myself!
I've actually got new pistons, seals and boots to go into my daily driver at some point, as I spotted a slight tear on one of the dust boots when I did the pads and discs. My plan is to finally refurb a pair of calipers by myself!
Tiglon said:
should I take out the pistons and seals as well in case dirt has gotten in, give it a clean in there and replace the seals, or is that not necessary?
Tiglon said:
Which part of the job does it seem like I'm not doing properly?
No one said you aren't doing it properly. My point is simply that if you're looking at driving 100,000 miles on what are already used calipers I'd want to inspect all the working parts - i.e. pistons out for inspection and a new seal kit.Panamax said:
Tiglon said:
should I take out the pistons and seals as well in case dirt has gotten in, give it a clean in there and replace the seals, or is that not necessary?
Tiglon said:
Which part of the job does it seem like I'm not doing properly?
No one said you aren't doing it properly. My point is simply that if you're looking at driving 100,000 miles on what are already used calipers I'd want to inspect all the working parts - i.e. pistons out for inspection and a new seal kit.Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff