Front and rear brakes

[Irish Mike]

Greeting friends. I have just bought myself a 1979 fiat 131 Series 1 here in Cape Town and after getting it home have found a number is issues with it and wondered if I could probe the minds of my fellow enthusiasts and try to get some suggestions as to how to imprve the brakes on this car.
First of all it came with some cracking 5.5j x 13 Abarth wheels so I would like to stay with them if at all possible.
The front are the standard solid disks with standard pads and I would like to know if there is a option from a more recent Lancia or Fiat which would allow me to use vented disks and perhaps four pot calipers?
On the rear the axle has been converted to accept the disks and handbrake assembly from a Fiat 124. The handbrake doesn't work at all and despite me hauling on it the other days could stop the car rolling back on a slight incline. I also managed to pop both the rear caliper seals. Is there a option from another Fiat to replace the calipers while retaining the manual handbrake or will I be compelled to look at a hydraulic handbrake?

Thanks

[Thotos]

The standard 131 brakes might not be great but they are good enough if working properly. I believe it's much easier to ensure that the standard brakes are working as well as they can be than to start re-engineering the braking system. As you have 13 inch wheels on your car you are very limited to the size of front disks you can use. Enzo has done some great work with modern disks and callipers on his Abarth replica  but with big wheels he has a lot more room to work with. Fiat 124 rear callipers are notorious for having a non-functioning handbrake. As the callipers get old and sticky the self-adjustment stops working and the handbrake becomes useless. But it's not just the handbrake that doesn't work but the rear brakes are probably not working well either giving you a long brake pedal and putting extra strain on the front brakes. I used to loosen the handbrake cable completely on my 124s and then get a crowbar on the handbrake lever and yank it as hard as I could several times to get it to adjust and "shock" it into action    My suggestion would be to get new or refurbished rear callipers, make sure the front callipers and all disks are in good condition and fit high quality pads and the braking system will be more than adequate for your car.

[TOAD]

Rear Calipers  

Those rear calipers need to come fully off when you release the handbrake, without this the auto adjuster will not adjust.  The brake will work from the foot brake, but run out of travel when the hand brake is applied,  ( I would think )

  If this is the case,  remove cable and check return spring inside of it I think, make sure the arm is coming all the way off, if it is, just rebuild the calipers and make sure its all freed off under the rubber boot.

  Remember you have to wind the rear pistons in, and not just push like the fronts, it's a combination of wind and push together.

[TOAD]

Try Uno turbo 1300  these have 227mm vented same size as standard 131,  I think I did this on one of our road cars and just needed new hoses making up, maybe i very little dressing back here and there with a file.

Oh, take the calipers and mounts as well for this

Brembo Group N = standard size better materiel with up-rated pads and I dispensed with the balance valve and put in an adjuster inside the car,  remember that although the disc's will lose heat quicker, the drums would have been for powerful so you will need a little more rear bias than standard.

  Roger........

[Tas131]

On the rear the axle has been converted to accept the disks and handbrake assembly from a Fiat 124.

The standard brakes are fine for a road car, even if you drive it hard, as long as the system is functioning well, and you have to have good quality pads. There are cheap ones available and you definitely get what you pay for in this case. I've got a disc rearend from a 132 in the back of mine, basically the same calipers as the 124, but a larger piston diameter. Even after rebuilding my calipers and having them well adjusted, the handbrake is not great. On a reasonable incline with the car facing downhill, the brake will hold, facing uphill so it rolls backwards it won't hold, I live with it and leave it in 1st or reverse.

[TOAD]

That's odd because my 124 's had the same disc brakes but I used to be able to handbrake those around, are we sure that the calipers which are mostly left along are adjusting correctly?   If there not this would make the handbrake go hard but not squeeze the pads as tightly as they should.

Try this;
  Leave the standard calipers and cables for legality, but plumb in a hydraulic handbrake, this will do away with the mechanical cable which will just hang there, but the rear brakes will come on like the foot brake,  this does work

  Roger......

[miro-1980]

Gents,


This is a pretty simple and reliable system and it works like magic provided it is re assembled properly and maintained properly:

1/ there is no rust present in handbrake line linkage
2/ the hand brake is properly adjusted
3. the return spring works    
2/ the pistons in the calipers are not rusted
3/ all seals are in good shape
4/ the system is bled
5/ the fluid had no water (recently replaced).
6/ the pads are in good shape
7/ the disk surface is flat (no grooves)
If all these are true both foot brake and hand brake must work well.

My 131 hand brake was always very sharp with both original drums as well as with Polski Fiat/Polonez rear calipers.

What you describe seems like a problem that should be diagnosed and fixed easily Please check if the following is true (in this sequence) and fix

1/ front foot brake works well (hard, not too much travel , blocks the front wheels easily)

2/ rear brakes ( should have around 35 % braking capacity with 65 % )for the front) Remember there is a mechanical balance adjuster, which often delivers less pressure than required but thus can be easily corrected)    

3/ the system is properly bled ( including the BMC !)

4/ the fluid is a DOT 4 and was replaced in the last 12 months

5/ the disk pads are in good shape (not worn, not scorched, not covered with a metallic glaze) If new - make sure you drive at last 100 miles before hard  
braking

6/ the disks have proper thickness and their surface is flat (with no grooves)

7/ the hand brake is properly adjusted

8/ the hand brake linkage is free of rust ( and moves smoothly in both directions, was not bent, burned by the exhaust , etc,)

9/ the he are no leaks on the caliper

10/ the piston and the cylinder in the caliper are totally (100% !) free of any rust
 

When you go through these ad correct all you find wrong you will have diagonosed and solved the problem.

I fully agree with Thotos and I believe that unless you do serious racing/rallying the combination of 227 fronts and 227 rear discs on floating 38 mm calipers are fine. If you must upgrade go to Uno turbo which can accommodate 240 / 252 vented front and  227 unvented rear.

But I would greatly advise to keep the original system unless the car is used for sports and you really push it to the limit.      

Once you get it right - you should be bothered by brakes problems as long as the disks and pads last.  

Miro

PS: I disagree with TOAD. I would not plumb a hydraulic handbrake into the system. if you choose to do so first diagnose and fix the brakes problem. A hydraulic hand brake is not a solution to all problems especially since you do not know what the problem is.  

Remember in case of any accident , if the car is inspected for possible technical malfunctions as causes or  factors which may have  contributed to the mishap they will find it. This might mean serious legal and potentially financial problems.

BTW: driving with an in line hydraulic hand brake is a very different experience ...    

M   

[TOAD]

You pays your money and you makes your choice.   

  But if you can't fad the standard brakes, your not driving fast enough and there fore don't need disc's all round anyway.

  Oh and by the way, Ford motor sport used to do this and there cars where used on the road between stages, it just depends how much slack is in the cable really, like the set up for twin throttle cables, one slightly slacker.

  But there you go

         Roger..........
   

[N. Dinis]

I feel the same problem, I own a S3 1.4 mirafiori, but with a racing S2 engine fitted in... and the lack of braking power scares me.... I was planing to use Delta HF turbo brakes and its a perfect fit... except for the wheels :s, I just haven't them fixed yet because I don't have found a good looking cheap 14" wheel set

[miro-1980]

Gents,  let me say this again :

You do not need to change the brakes on 131 (be it a 1.3, 1.4, 1.5, 1.6. 1.8, 2,0 or 2.5) for normal street use.

They are very effective, quite satisfactory in normal street driving use.

If they are not effective see below. There is something wrong in the system that can be easily fixed.

If you need to change go for Uno turbo setup which fits 13" wheels.

If your problem is with old braking fluid, worn discs, bad pads, rust in calipers , rusted BMC, or poor vacuum boost - no new caliper will change it.

Money saving tip : first fix the system you have and make it perform 100% - if this is still not enough then think about upgrading. Any other approach will be  quite costly and may be  quite dangerous.

Miro    

[TOAD]

Sorry Miro for disagreeing with you    

  Although I do accept what you say about 131's being driven to the shops though, the standard brakes would be fine.

  Some of us don't buy Mirafiori's just to drive nicely through the country side on a fine day,   Isn't that a nice tree dear  

[miro-1980]

I could not agree more ...

So the key question is will always be:

How do you drive your 131 - weekend pleasure / or weekend track-day ?

These are two separate stories, however until you get your standard brakes working at peak performance you will not know if this is emough , and if the problem is not the calipers - if you upgrade the calipers the problem will remain unsolved ...

 Total agreement ?

Miro 

[TOAD]

Miro,   how about this, you must know at what power level the brakes need uprating, how about doing a thread of these changes so that people can change things properly the first time?    Lets face it, you don't need to be any sort of expert the figure out that even if you fix your standard brake system, it will never slow a properly driven Guy Croft engine     

  With that in mind you wouldn't bother repairing the standard brakes would you, so how about that Braking upgrade thread then Miro?  get them doing it properly.

  Roger.........

 

[miro-1980]

Roger, what's true is true ...

 
I went to all  disc brakes initially when the bhp count was around 120 and  started upgrading my brakes when my bhp count exceeded 140 (to Uno turbo), and did a major upgrade when suddenly I got over 180 bhp line .

Nevertheless  I believe that for most people standard brakes are fine. I have standard in my 2.0 124 spider and have no intention to upgrade them (just to make them perform as they should.)  For club rallying and club racing this is really sufficient.

(Maybe pads could more sporty, and the discs cut/drilled and maybe rubber lines could be replaced with stainless steel braided, oh, and the brake fluid could be more heat resistant .....  

But seriously , let's start such a thread ...

Miro      

[ZFA16V]

Not taking sides here....my 131 track club car with slicks runs the standard disks with good quailty pads and dot 4 fluid and rubber hoses.
Also running rear drums and pulls up suprisingly well.
Still can improve with stainless lines/drilled rotors and importantly....some cooling.
Factory brakes are fine to a point unless you have hosepower/speed.