Sorry to hear you're having problems with the stretching. I wasn't particularly scientific in my approach to stretching the springs. I clamped one end into a large vice on my bench and slipped a screwdriver through the other end and pulled. I remeasured the spring and increased the amount of force until they were 4 to 5 mm longer. If you haven't got a vice, you could improvise by screwing a large screw into a strong fence post (or wall) and hook the spring over the head to give a firm anchorage. You have to give them a good tug! Pod 500,in an earlier post on this thread, said that he over extended the spring by two inches to to get a permanent change in length of 5 to 6mm. I spent about 15 minutes stretching all 8 springs.

My brake shoes were manufactured by RAL in Italy and the friction washers on the adjusters appear to be too weak. It must be a known problem as some of the parts suppliers list an alternative make of shoes with more robust adjusters. I haven't a clue who the manufacturer is or if the brake shoes are any better. I've quickly come to the conclusion that although the parts supply for the Fiat 500 is very good some of the parts aren't manufactured to the same quality as the originals!

Thanks Hobo. That is useful. I did find the old springs in the bottom of the bin and compared them to the new and there is about 2mm difference. For the time being I have put these old springs back on the rear wheels (didn't have time to do the front yet) and may get the car out when the weather is slightly less wet and see if it makes any difference. In the meantime I have a couple of the new springs stretching and am leaving them for 24 hrs to see if that works (will check tonight) - even using a vice and the adjusters on the workbench to stretch them mechanically I can only get them pulled about an inch/2.5cm....you must have some serious muscle ...all the springs in 15 minutes??

AndrewRL said:

For the time being I have put these old springs back on the rear wheels

Click to expand...

If the springs aren't damaged and the shoes don't catch or bind in normal running you could leave it that way.

The original friction adjusters were removable and I believe that the friction material was clamped between two threaded discs. This was fitted using a special "spanner". I bet that you would have been able to adjust the amount of grip that the adjusters had so that the grip was a better match to the pull of the springs.

The key is to use the car a lot so that the springs get a regular workout.

Before doing anything drastic, I would have used an easy bleed kit , put 15 presses on the brake pedal for each wheel and look at the volume of fluid from each wheel..making sure the fluid reservoir is full all the time.. this would enable maximum bleeding of pipes and eliminate all the air , as well as you would know if any of the flexible hoses are actually blocked.

I worked for a Fiat Main Dealer back in the '70's-'80's.

As Peter says above, there were different type of adjuster mechanisms used.
The early ones were held together with a circlip and could be changed over to the new brake shoes if the shoes came without adjusters fitted. Fiat actually supplied an official special tool to compress the spring to remove/refit the circlip. This tool looked a bit like a balljoint/trackrod tool, i.e. a fork with a screw to apply pressure. It might be possible to use a valve spring compressor or rig something up with 'G' (or is that 'C') clamps? If working on these, remember that the 'square' side of the circlip faces outwards. I learnt this lesson the hard way!

Later adjusters were threaded, later still (aftermarket) were swaged in place, therefore not designed to be removed.

I don't recall ever fitting new return springs at the dealership, I guess the springs didn't give any trouble. I did replace some springs on my own cars at home later on. And I did encounter problems similar to what others have described above.

How to check if the springs are too strong (or too short, which will have the same outcome):- Try levering the shoes apart so that they move through the adjusters. See if the shoes stay in their new positions. If they slide back through the adjusters, then the springs are too strong (or too short).

Personally I'd refit the old springs if still to-hand. These may still pull the shoes back through the adjusters if the adjusters don't grip the shoes firmly enough. Easiest way to extend the springs is to heat a couple of coils to red hot (a gas blowtorch might be sufficient) and then stretch them the required amount. )(best do this to old springs rather than wreck new springs).

I've played around with adjusters a bit in the past. With the types that can be disassembled, I inserted an additional washer to increase the spring pressure. Another time, I removed the adjusters and used a sharp cold chisel to cut serrations in the surface of the brake shoe where the adjuster friction washers try to grip. This worked well.

If the adjusters can't be removed, I think I'd try cleaning any paint from the areas where the friction washers sit and allow or arrange for some surface rusting to occur (phosphoric acid/Baker's Soldering Fluid anyone?). This could be done in 2 stages, move the adjusters fully one way, treat the surfaces exposed, then move the adjusters fully the other way and treat the remaining surfaces.

P.S. Here's a tip that might help those having difficulty in removing/refitting brake shoes return springs.

Forget about levers, visegrips, pliers etc. You'll only end up hurting yourself.
Use a screwdriver, but not just any screwdriver! I favour a cabinet maker's style i.e. straight shaft, same diameter all the way to the tip, approx. 100mm (4 inch) with a straight tip and approx. 5.5mm (3/16ths) diameter. To remove a spring, push the screwdriver tip into the hole where the spring hook is fitted, try to get the tip under the spring hook. Twist the screwdriver to disengage the spring hook and prise it out using the screwdriver.

To refit a spring :- Fit spring roughly in place behind the hub, insert one end of the spring into one brake shoe, slide screwdriver through the other end of the spring at an angle, place tip of screwdriver into hole in brake shoe, swing screwdriver to extend spring and allow spring to slide down screwdriver shaft and pop the hook end of the spring into the hole. Job done. Easy-Peasy, takes seconds, no damage to me or the car.

I'm not being smug! As an apprentice, I struggled with brake springs, often ending up bleeding One day, an older,wiser Mechanic showed me the above trick. Boy, did I feel like a fool for not having figured it out for myself! Often think of that old guy when I use 'his' trick!

For those who like buying tools There are special pliers available for dealing with brake shoe springs - 2 types, one for riveted linings (doesn't apply to Fiats), one for bonded linings (does apply to Fiats). But not necessary if you use the above screwdriver trick.

If I knew enough about computers etc. I'd post a video of some tips I've picked-up along the way. But I don't so I can't! (same reason why I don't post pics )

Al.

Sorry for resurrecting this (again )

I did put the old springs back and at the same time noticed that they were 2mm longer than the new ones. One of the front wheels must have had them replaced "recently" as the "old" springs were the same 10cm as the ones I purchased (would that explain why the car used to pull to one side?)...so I was back to stretching those.

Anyway, I cracked the stretching thing (by putting a thick 6inch nail underneath my trolley jack and one through the arm hinge, connecting the spring to the nails and then using the jack to stretch them...a stretch of 4.5cm to 14.5cm produced a permanent 2mm increase in length...for future reference ).

Anyway....slightly longer springs back on and....no difference . Still very long travel with no difference if pedal pumped (so doesn't need bleeding??). So, do I stretch them more or try something else? I do have a replacement master cylinder which came with the kit - I didn't put this on as I couldn't remove the pipe union nuts and didn't want to risk damaging them. I could take it to a mechanic and get them to change the cylinder. Do you think this may make a difference (the insides of the old cylinder possibly damaged when pumping new fluid through the new flexible tubes and wheel cylinders?)??

Of course, the brakes may be fine and that is the way they are supposed to be. They do stop the car but don't feel as firm as they used to (although they do stop the car in a straight line now!).

Being that I was the instigator of this discussion, I thought it courteous to pass on my findings as I cured my problem. A colleague pointed out to me that some of the new "pattern" brake shoes are being supplied with thinner linings on them than O.E.---this will, of course, exacerbate the problem.
When I was at the 'Festival Italia' at brands (in August) I had a lengthy conversation with Anton, the MBG chief mechanic. The upshot of this 'chat' was the fact that Middle Barton Garage can now supply brake shoes for the 500 brakes (but not, sadly, for the 126) with Ferodo linings. These are about 1mm thicker than the 'pattern' parts. It may not sound a lot, but it won't help the situation if the linings are thin.
The brakes on my 'wee beastie' are 126, so I looked for the best available and found shoes made by "METELLI" (Axel Gerstle). These seem to have thicker linings and 'grippy' self-adjusters. I also (again, as per Anton's suggestion) slightly stretched the top brake-shoe return-springs. I now have a very acceptable brake pedal and stopping performance.
Lastly, I made sure that the hand-brake was correctly adjusted--at JUST 3 clicks I may have slightly OVER adjusted, but the adjustment of the hand-brake will affect the effect of the rear shoes.

Thanks Hobbler

So...are you saying that maybe a bit more stretch may solve this? As the kit (with new shoes, springs and cylinders) came from Ricambio in Surrey I assume good quality but can try another couple of mm I guess (although I am not relishing taking it all apart again!). Glad I bought some spare front hub nuts

I'm not sure that minimal gains such as 1mm thicker linings are really the solution unless you plan on never using the brakes. After all, the linings are supposed to be usable until there's maybe only a few millimetres left of them.
The key features are that the linings should be sitting just short of contact with the drum at rest and that the friction material should follow the inner curvature of the drum as accurately as possible. The latter should develop over time even if there is a fairly poor match after a fresh installation. The brakes should be treated gently at first in order to allow the high spots of the linings to wear down first.
You seem to have the ongoing battle to get the balance of the pull of the return springs and the grip of the friction washers under some control. So assuming that the linings are now as close as they can be to the drum inner surface, it is worth checking that the tips of the pistons of the slave cylinders are in contact with the tips of the brake shoes when at rest. There is a coil spring inside the cylinder which seems to be intended to apply gentle pressure which keeps them pushed out even when the brake fluid isn't under pressure. It is possible that the cylinders or spring could bind, which would mean some wasted pedal travel when applying the brake.
The handbrake operation is meant to be independent of the footbrake and if over-adjusted it seems possible that you might cause the brakes to be catching all of the time for the sake of forcing the shoes closer to the drums.

Just a (belated) update. Having (a) put the old springs back on and stretched what looked like a newer pair so they matched the others and (b) forced the shoes apart as best I could there was still no improvement. In the end I took the car to a recommended workshop to see if they could solve it. I also gave them the new master cylinder which I had not put on (couldn't remove the union nuts and didn't want to damage them) in case that was the issue.

They looked at what I had done and said the brakes/cylinders were fitted OK (phew!). They then decided to bleed the system again and, apparently, got a lot of black "gunge" coming out of the rear nearside (from what???). Anyway, having bled the whole system again the brakes are perfect Well...perfect for a set of drums! Total cost £85.

Moral of the story? I guess that bleeding brakes is one of those things that sounds easy in theory but is not an easy thing for one novice.

Actually I guess the true moral of the whole episode is...if it ain't broke, don't try and fix it

Ignoring that though I'm moving on to the next stage on my tinkering journey.

Easy bleed kit costs less than a tenner.. and it's an extremely quick and easy one man job

Re:- Fitting brake shoes with slightly thicker linings....

A long time ago, I worked for a business which relined brake shoes and clutch discs. Mainly rivetted but also bonded, which is why I mentioned (in an earlier post) removing/refitting the self-adjuster mechanism to Fiat brake shoes.

Lining material came in different thicknesses, widths, hardness/co-efficient of friction etc.

Bear in mind that brake drums wear. Sometimes they get skimmed in order to correct ovality. I always check any new brake shoes I'm about to fit by holding them against the inside of the brake drum to see that the curvature of the lining matches the curvature of the brake drum. In the Classic Bike and Car restoration world, it's not unusual to skim drums, possibly fit oversize linings and then turn/skim/linish the linings to fit the drum diameter, when replacement parts are unavailable. This technique can make a world of difference to how well drum brakes work.....

P.S. For those of you who have spent much time struggling to fit Fiat brake shoes and get them adjusted/working correctly, spare a thought for the unfortunate Mechanic back in the day who was allowed maybe 1 hour to do all 4 brakes and have them working correctly. (No excuses permitted!).....

AL.