Technical Brake issue

[FabAni]

Hello Everyone!

Hope you are all well

We have noticed recently that the brake pedal in our Fiat 500 F (1971) becomes a bit harder (it brakes absolutely fine) and after a few minutes using it it becomes softer as it usually is. We noticed it seems to be happening when we turn the car on and than after 5 minutes it comes back to normal. Also, it doesn't always happen. Very random!

We were just wondering if you know what it could be and if you think it something that we should get checked out?

Thank you very much in advance!

 

[FabAni]

Hey guys, just checking if anyone has got any idea? Thank you

 

[Fatcatvera]

Hey guys, just checking if anyone has got any idea? Thank you

This could be due to a number of things. Some things to check:-
1. Bleed the system to make sure there is no air in it.
2. Any obvious signs of fluid loss at master or slave cylinders?
3. Are the brake shoe springs too strong such that they are overcoming the friction discs, causing the shoes to pull too far back from the drum? This will cause a long pedal. You'll need to take each drum off to check for this. See my post here at top of page 2. https://www.fiatforum.com/threads/spongy-brakes.457736/post-4761330

 

[the hobbler]

This could be due to a number of things. Some things to check:-
1. Bleed the system to make sure there is no air in it.
2. Any obvious signs of fluid loss at master or slave cylinders?
3. Are the brake shoe springs too strong such that they are overcoming the friction discs, causing the shoes to pull too far back from the drum? This will cause a long pedal. You'll need to take each drum off to check for this. See my post here at top of page 2. https://www.fiatforum.com/threads/spongy-brakes.457736/post-4761330

Over-strong brake-shoe return springs is a common problem these days---the 'pattern' brake-shoe springs are too short, and as a result are over-strong when stretched (when the brake pedal is used). The result is that these 'pattern' springs pull the brake shoes too far back away from the drum. Combine that with the fact that (a) some of the 'pattern' brake -shoes have slightly thinner linings than the Factory originals and (b) I am convinced that the'friction-pads'in the 'self-adjuster'are not as 'grippy' as the original factory parts and you will have a problem getting a good brake "pedal". The spring problem can be overcome by either using the original springs if at all possible OR---CAREFULLY stretch the 'pattern' springs out to the same length as the originals. To overcome (a) have a word with Tony at Middle Barton Garage---he had a batch of brake shoes made for the 500s to original Factory specs. Sadly, I do not know an easy way to overcome (b).