Thanks. There are nipples in the pads and the pistons are set before assembly.
Technical Hand brake
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Technical
Hand brake
I agree with your thinking about the spring needing to grip the nut in one direction and freewheel in the other.I love the input and information and it is much appreciated.
I'm not sure how you would see it but my thinking is that it should tension and grip in one direction and freewheel in the other. The collar (nut) and/or spring is/are worn, so this is making the grip of the interference is failing when applying the handbrake, thus the nut is turning too freely and is slipping in the spring and by not allowing the spring to tension up a grip the nut sufficiently to wind it out and take up the slack so to speak.
Have you actually dismantled the auto-adjuster or are you relying on a parts see-through diagram when describing the internal parts and concluding that the spring is slipping on the nut?
Would it be possible to 'tighten' the 1st few coils of the spring (opposite end to the spring tail) so that it can grip the nut sufficiently? (possibly by winding the spring around something of a smaller diameter - with or without using heat?
Maybe send an eMail to Arnold Classic shop to enquire if the rear brake caliper piston, they list, includes the internal adjuster?
I noticed that the Midwest-Bayless illustration I provided of the (secondhand) caliper internal adjuster parts, shows the nut and spring as being together not as separated parts, I wonder if this has/hasn't any significance.
I did some searching on the (U.S.) McMaster-Carr w/site, they hold massive stocks of various fasteners/consumables, under the heading of Torsion Springs and there was some info. on r/h versus l/h wound springs, that the length changes and that it tightens around the pivot pin/shaft when the spring is compressed (similar to what I suggested in an earlier post) but they didn't have any springs similar to the Fiat brake adjuster spring - I was thinking that maybe altering a spring with 2 legs to one of 1 leg, shorten the remaining leg and heat/bend a 90* on it and select a wire gauge and spring diameter to replicate what Fiat used in the rear brake caliper, might work? But there's a huge variety of sizes, so you'd need to have a Fiat spring to measure first... (I realise you probably don't want to order from the U.S. due to customs etc. but I was trying to find something that could be used).
In the absence of a source of the necessary parts, the quickest fix would obviously be to opt to buy a new caliper.
Alternatively, if the handbrake is working OK on the left and partly OK? on the right, the car could still be used/driven, giving you more time to try to find the necessary parts or another solution.
.
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Have you actually dismantled the auto-adjuster or are you relying on a parts see-through diagram when describing the internal parts and concluding that the spring is slipping on the nut?I agree with your thinking about the spring needing to grip the nut in one direction and freewheel in the other.
Have you actually dismantled the auto-adjuster or are you relying on a parts see-through diagram when describing the internal parts and concluding that the spring is slipping on the nut?
Would it be possible to 'tighten' the 1st few coils of the spring (opposite end to the spring tail) so that it can grip the nut sufficiently? (possibly by winding the spring around something of a smaller diameter - with or without using heat?
Maybe send an eMail to Arnold Classic shop to enquire if the rear brake caliper piston, they list, includes the internal adjuster?
I noticed that the Midwest-Bayless illustration I provided of the (secondhand) caliper internal adjuster parts, shows the nut and spring as being together not as separated parts, I wonder if this has/hasn't any significance.
I did some searching on the (U.S.) McMaster-Carr w/site, they hold massive stocks of various fasteners/consumables, under the heading of Torsion Springs and there was some info. on r/h versus l/h wound springs, that the length changes and that it tightens around the pivot pin/shaft when the spring is compressed (similar to what I suggested in an earlier post) but they didn't have any springs similar to the Fiat brake adjuster spring - I was thinking that maybe altering a spring with 2 legs to one of 1 leg, shorten the remaining leg and heat/bend a 90* on it and select a wire gauge and spring diameter to replicate what Fiat used in the rear brake caliper, might work? But there's a huge variety of sizes, so you'd need to have a Fiat spring to measure first... (I realise you probably don't want to order from the U.S. due to customs etc. but I was trying to find something that could be used).
In the absence of a source of the necessary parts, the quickest fix would obviously be to opt to buy a new caliper.
Alternatively, if the handbrake is working OK on the left and partly OK? on the right, the car could still be used/driven, giving you more time to try to find the necessary parts or another solution.
.
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Yes I have and I didn't see a problem but at the time I was unsure on its workings. It's one of those where you need to have the eye of experience. I will certainly be taking another look and see if it can be tweaked just for curiosity before I order a replacement part.
I will be in touch in the not to distant future to let you know on my findings
I love the input and information and it is much appreciated.
I'm not sure how you would see it but my thinking is that it should tension and grip in one direction and freewheel in the other. The collar (nut) and/or spring is/are worn, so this is making the grip of the interference is failing when applying the handbrake, thus the nut is turning too freely and is slipping in the spring and by not allowing the spring to tension up a grip the nut sufficiently to wind it out and take up the slack so to speak.
Okay, I removed and completely stripped the suspect rear caliper probably with no avail, nothing appeared to show any wear, unfortunately my shipment of parts came minus the ordered and paid for rear brake pads
so a test isn't possible at the moment. A couple of things worth a mention is that the full travel of the brake lever gives 3.24mm on the piston and the other is that I think the caliper is probably a remanufactured unit.I found this description of how the rear brake caliper handbrake auto-adjuster works in an old 'Autobooks' workshop manual for the Fiat 124 Saloon - seems to be much as I suggested in an earlier post. And, as you suggested, the spring needs to be able to grip the nut for the auto-adjuster to work.
Here's the instructions for reassembling the rear brake caliper:-
Note:- there are slight differences between the very early and later rear calipers e.g. in how the handbrake lever pushes on the handbrake plunger (later version has a wedge piece interspersed between a groove in the lever pivot shaft and the h/brake plunger; Item 1, flat caliper retaining spring not? used
on later calipers; early calipers had a spring clip retaining the auto-adjuster inside the caliper piston, later calipers had a spun-in disc preventing disassembly (see image below from Midwest-Bayless showing internal parts of early, dismantlable type caliper) etc.
Here's the instructions for reassembling the rear brake caliper:-
Note:- there are slight differences between the very early and later rear calipers e.g. in how the handbrake lever pushes on the handbrake plunger (later version has a wedge piece interspersed between a groove in the lever pivot shaft and the h/brake plunger; Item 1, flat caliper retaining spring not? used
on later calipers; early calipers had a spring clip retaining the auto-adjuster inside the caliper piston, later calipers had a spun-in disc preventing disassembly (see image below from Midwest-Bayless showing internal parts of early, dismantlable type caliper) etc.
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Item 4 whatever it is on the picture above is not in my internals. I am confident that my spring is a good solid fit to the collar and capable of doing what we suspected. My caliper is different in the fact there is a separate pawl between the pivot pin and the plunger.
The epilogue. After mutli strip downs of the handbrake piston without finding any apparent fault I bit the bullet and obtained a new caliper and the problem was solve. The whole episode beggars belief, on the bench the spring would tension tight on to the collar and would freewheel in the opposite direction. As I stated, I am sure this caliper was a remanufactured unit and I feel the problem was down to this but I had nothing to compare with. Hey ho!
hi
and a bit late for you,
but what worked for me was foot hard on brake pedal,then whilst holding down,pump the handbrake lever several times to take up the slack in the adjuster.
cheers.
and a bit late for you,
but what worked for me was foot hard on brake pedal,then whilst holding down,pump the handbrake lever several times to take up the slack in the adjuster.
cheers.
When handbrake ratchet faulty on brake calipers I usually find more cost effective to just "bite the bullet" and fit a new one.
Thanks but I tried this more times than I wish to remember
Tend to agree with you, it was just baffling my engineering ability but the car is new to me and I had no history apart from it has been stood for 4-5 yearsWhen handbrake ratchet faulty on brake calipers I usually find more cost effective to just "bite the bullet" and fit a new one.
I understand, it is always good if you have a engineering challenge and can fix it. That is something over the years I have applied to many things from motor vehicles, to steam cleaners, sewing machines and even computers, quite often with success. I usually find the same fault finding logic can be applied.
It must be in the genes, one of my sisters could locate the faults in a poorly written computer program, although programming is not something I could get into, it was more the physical side.
You could have stripped the caliper from the opposite side and swapped parts between the 2 sides to see if you could identify the issue? Might have ended up having to buy 2 new calipers
I wonder if the other caliper was a possibly 're-manufactured' unit or an original and therefore didn't cause any problems with the 'adjusting up'.
I also wonder if the absence of Item 4 in my post #25 above had anything to do with the issue, or perhaps the disc springs (same post) were weakened or incorrect in number? I did note your comment about the llustration of the internals of caliper not matching what was present in yours - I think I did mention that there were differences between early and later calipers, especially in the area of the actuating arm and how it pushed on the threaded plunger.
I used to marvel at those who could afford to buy new calipers etc all around when it was much cheaper to just fit new seals - I used to assume their decision was because they were cash rich/ time poor. But fitting new calipers sure avoids any aggravation. (plus they look nice!).
At this point, I imagine that if you never ever again saw the insides of a Fiat 124 rear brake caliper, it wouldn't be too soon.
I think you are correct on all points #124BC1, but be sure that I did try very hard not buy a replacement and was definitely not letting myself in to buying two.You could have stripped the caliper from the opposite side and swapped parts between the 2 sides to see if you could identify the issue? Might have ended up having to buy 2 new calipers
I wonder if the other caliper was a possibly 're-manufactured' unit or an original and therefore didn't cause any problems with the 'adjusting up'.
I also wonder if the absence of Item 4 in my post #25 above had anything to do with the issue, or perhaps the disc springs (same post) were weakened or incorrect in number? I did note your comment about the llustration of the internals of caliper not matching what was present in yours - I think I did mention that there were differences between early and later calipers, especially in the area of the actuating arm and how it pushed on the threaded plunger.
I used to marvel at those who could afford to buy new calipers etc all around when it was much cheaper to just fit new seals - I used to assume their decision was because they were cash rich/ time poor. But fitting new calipers sure avoids any aggravation. (plus they look nice!).
At this point, I imagine that if you never ever again saw the insides of a Fiat 124 rear brake caliper, it wouldn't be too soon.
The replacement is probably a Lada caliper and if this is the case there are much cheaper outlets than going through so called Fiat suppliers.
If it's any consolation a Lada brake caliper is better than a Moskvich wheel cylinder, we were dealers for them as well and used to spend two days on a PDI to make them safe enough to sell.;(
