The Fiat 500 Twinair (2011) failed MOT on corroded rear subframe.
Discovery No 1: If it is rusty you need to check the backplate every time you open up the brakes.
While changing the subframe I removed the brake drums which were a bit rusty and decided to clean them up, maybe repaint them. While wire brushing one of the back plates that holds the brake shoes a lump fell away leaving a hole I could put my pinky through. Not wanting my brakes to disintegrate while in use I decided to change the backplates.
Discovery No2: There is more than one type of drum brake on the Fiat 500 (312). Worth bearing in mind when buying parts.
I decided to purchase a reasonable condition second hand subframe assembly to get replacement back plate, automatic brake shoe adjuster mechanism. brake lines, clips etc. Imagine my surprise when I found the backplate, hydraulic cylinder, brake shoes and automatic adjuster were all different from what was fitted originally.
Discovery No 3: Both types of COMPLETE brake drum assemblies bolt straight on with no fuss.
In the end I decided to get the reasonable second hand back plate cleaned and powder coated. Came up lovely. This led to me deciding to renew all component, requiring correct selection of parts. Finished item bolted straight on and works just fine.
Discovery No 4: The two types of brake drum assembly are:
Lockheed (the original disintegrating assembly).
Bosch (the replacement that got powder coated.
The only drum brake part that fits both assemblies is the outer drum. Nothing else is interchangeable.
If you are tackling a subframe change or any work on the rear brake lines be warned, the joins can seize solid and require replacement of hoses and/or lines after separation. This included spraying the relevant joins with Bulldog BDX releasing spray every day between two weekends and using quality brake line spanners. I ended up fitting Goodridge hoses and renewing the lines that connected to the drums.
Apart from the corrasion at the join, when trying to undo the nut on the brake line it seemed to have seized on the pipe itself and resulted in the pipe being ruined when the nut was turned. I saved the main lines running under the car by cutting the flexible hose and rotating it rather than the brake line nut. When fitting the new subframe I built up the brake lines with the subframe in position to allow me to turn the new hose rather than the brake line nuts.
If I was relying on the car for transport and had to do this job in a weekend the brake line issue on its's own would have been a disaster. Assess the job by giving your nuts a tweak before you start. Ha Ha.
Discovery No 1: If it is rusty you need to check the backplate every time you open up the brakes.
While changing the subframe I removed the brake drums which were a bit rusty and decided to clean them up, maybe repaint them. While wire brushing one of the back plates that holds the brake shoes a lump fell away leaving a hole I could put my pinky through. Not wanting my brakes to disintegrate while in use I decided to change the backplates.
Discovery No2: There is more than one type of drum brake on the Fiat 500 (312). Worth bearing in mind when buying parts.
I decided to purchase a reasonable condition second hand subframe assembly to get replacement back plate, automatic brake shoe adjuster mechanism. brake lines, clips etc. Imagine my surprise when I found the backplate, hydraulic cylinder, brake shoes and automatic adjuster were all different from what was fitted originally.
Discovery No 3: Both types of COMPLETE brake drum assemblies bolt straight on with no fuss.
In the end I decided to get the reasonable second hand back plate cleaned and powder coated. Came up lovely. This led to me deciding to renew all component, requiring correct selection of parts. Finished item bolted straight on and works just fine.
Discovery No 4: The two types of brake drum assembly are:
Lockheed (the original disintegrating assembly).
Bosch (the replacement that got powder coated.
The only drum brake part that fits both assemblies is the outer drum. Nothing else is interchangeable.
If you are tackling a subframe change or any work on the rear brake lines be warned, the joins can seize solid and require replacement of hoses and/or lines after separation. This included spraying the relevant joins with Bulldog BDX releasing spray every day between two weekends and using quality brake line spanners. I ended up fitting Goodridge hoses and renewing the lines that connected to the drums.
Apart from the corrasion at the join, when trying to undo the nut on the brake line it seemed to have seized on the pipe itself and resulted in the pipe being ruined when the nut was turned. I saved the main lines running under the car by cutting the flexible hose and rotating it rather than the brake line nut. When fitting the new subframe I built up the brake lines with the subframe in position to allow me to turn the new hose rather than the brake line nuts.
If I was relying on the car for transport and had to do this job in a weekend the brake line issue on its's own would have been a disaster. Assess the job by giving your nuts a tweak before you start. Ha Ha.
(Oh matron! )Like death and taxs its pretty much unavoidable
a large can of release spray is your best friend!- along with his brothers wire brush and stone chip paint!.
