So I was out driving with the
SuperCarDriver guys the other week in my Ferrari Dino 308 GT4 starting pulling to the right (drivers side UK) under braking. I've never really looked at the front brake callipers so I suspect it is time for a rebuild.
The original brake callipers on the 308 are made by ATE and are in fact the same as fitted to the late 1970's Porsche 911 which means that rebuild kits and in fact new callipers and pistons are easy to come by.
So I pulled the left hand calliper pads to take a look and sure enough one of the pistons was seized. So definitely time for a rebuild.
Whilst the hydraulics were still connected and with the pads removed I used the brake pedal to push the pistons out as far as they would go as getting seized ones out once the callipers is removed can be hard.
Next thing was to remove the calliper and remove the pistons. It's normal to use compressed air to pump the pistons out of a removed calliper - clamp the one you don't want to come out first.
This worked finally and the seized outer piston came out. A bit of air also removed the free inner piston to reveal the cause of the seizure - rust of course.
You can see that there is no rust inside the cylinder area but you can see the rust on the thin section after the groove where the hydraulic seal goes. I used a dremel type drill to remove this surface rust - being careful not to mark the inner cylinder area. I also cleaned out the seal groove which showed some signs of rust.
Clean up and rebuild in the next post :)
Our expanding group of super car drivers released their first magazine. With 80+ pages or real cars and real owners this is a good start to the public facing side of the club. My Ferrari Dino 308 GT4 is featured pp40-47 in an article about 30 years of Ferraris - nice.
After the brake rebuild I checked the car over and took it for its annual inspection (MOT) which it duly passed to my delight - well I would hope so given the amount of work I do on the car. The only comment was that it took some time to pass emissions and the inspector had to run the car up warm. Of course the carbed 308 Ferraris aren't particularly happy at idle and can easily get fouled plugs. The car has not seen any long high speed runs in the last few months so it's no surprise that emissions was touch and go. The piston rings on older cars need some use to get them sealing properly and my car could also do with an oil change which often effects emissions. I'll get on with that when the weather warms up.
Looking at the brake pistons it was clear that I would benefit from fitting new ones. Remember that they are the same as Porsche 911 ones (47.97mm x 30 mm) and I bought four new ones and the required seal kit from a company called BiggRed - total cost around £120.
Fit the new hudraulic seals and pistons with a little brake fluid on the piston as you push it in. I also add some brake grease (red) around the piston as I finally push it down into the calliper housing.
Then fit new dust seals and spring clips - these can be a PITA to fit.
After rebuilding both front callipers with new stainless steel pistons and new seals I decided to also fit new discs bought from the BremboShop and of course new pads (same as Alfa Spider).
So I was out driving with the SuperCarDriver guys the other week in my Ferrari Dino 308 GT4 starting pulling to the right (drivers side UK) under braking. I've never really looked at the front brake callipers so I suspect it is time for a rebuild.
So I pulled the left hand calliper pads to take a look and sure enough one of the pistons was seized. So definitely time for a rebuild.
Next thing was to remove the calliper and remove the pistons. It's normal to use compressed air to pump the pistons out of a removed calliper - clamp the one you don't want to come out first.
You can see that there is no rust inside the cylinder area but you can see the rust on the thin section after the groove where the hydraulic seal goes. I used a dremel type drill to remove this surface rust - being careful not to mark the inner cylinder area. I also cleaned out the seal groove which showed some signs of rust.
Posts
