Technical Panda bleeding

[koalar]

Handbrake is now excellent, about 6 clicks and there's no chance of it moving

6 sounds a lot. But I don't have the 100hp.


too much normally has a knock on affect with brake travel


anyone know the proper adjustment ????

 

[DaveMcT]

I wind out the brake piston until it fits the brake pads thickness. Set the piston slot to 12-3-6-9. It's its a struggle to fit unwind it a 1/4 turn. Then lightly tighten the caliper holding bolts and check the hand brake lever movement.

 

[varesecrazy]

To be honest I though they all had ABS (in UK anyway). Can't say for elsewhere though the base cars in Italy are just tin boxes with seats inside. You pay extra for door mirrors and rubber mats.

The UK 169 in the launch year were high trim..but no ABS

by mid 2006 our 2004 Active
Was the same spec as new Dynamic..

The Actives from that point on were a bit sparse.. but prices up by @£1k

 

[Wazzzer]

6 sounds a lot. But I don't have the 100hp.


too much normally has a knock on affect with brake travel


anyone know the proper adjustment ????

I had a look at various MOT sites and the general concensus seemed to be 6 to 7 clicks was acceptable. I can see what you mean about it affecting travel though, I'll see what a professional says later and report back.

 

[Jockcl500]

I had a look at various MOT sites and the general concensus seemed to be 6 to 7 clicks was acceptable. I can see what you mean about it affecting travel though, I'll see what a professional says later and report back.

I have always set manual handbrake levers at 4-5 clicks, I would say 6-7 means it needs adjusting.

 

[Wazzzer]

I had a look this evening and the cables are a bit loose in the arm on the caliper so I'll adjust them up a little after work

 

[DaveMcT]

I had a look this evening and the cables are a bit loose in the arm on the caliper so I'll adjust them up a little after work

Winding the brake piston back to the stop even with new pads can leave too much slack. It also causes uneven braking across the axle. Set them both with similar "clearance" to the pads. If you wind them right back with part worn pads there can be a huge gap causing slack hand brake lever.

 

[koalar]

I thought they were self adjusting if you slacken the cable off first ?? Then re adjust

I could be miles off as I haven't worked on the fiats rear disc brakes. But thats how all other makes have worked

 

[DaveMcT]

I thought they were self adjusting if you slacken the cable off first ?? Then re adjust

I could be miles off as I haven't worked on the fiats rear disc brakes. But thats how all other makes have worked

Before doing my back brake I'd have agreed with you. Wind back the piston, fit pads, job done. How hard can it be?

I did that and hand brake lever was way too high. I already had the centre console out of the car and noticed the handbrake cables balance bar was at a heck of an angle.

Turning the new caliper piston to fit the part worn brake pads sorted out the balance bar and gave me a normal hand brake lever.

 

[Wazzzer]

Sorry to bring this to the top again but I thought I'd report my findings.

After having a very spongey pedal since replacing the calipers I thought I'd give it a re-bleed today.

As stated in other threads the rear calipers seem to like holding on to the air and I had loads come through. I gave them a good tap while bleeding and it seems to have helped a lot.

I got a bit of air out of the fronts but nowhere near the amount from the rears.

After going up the road and testing the difference is night and day. I think they'll need another bleed just to be sure but they're already 100% better than before.

So if you have a spongey pedal just be patient and give the brakes a few bleeds and all will be well

 

[DaveMcT]

If you like a firm brake pedal, fit HEL braided hoses. 600mm long hoses with four grommets will do each side at the rear with off the shelf Panda dimension hoses at the fronts.
The downside is you cant use a hose clamp while servicing the brakes. I use a bolt through the rear banjo and a cap at the front.

 

[Pugglt Auld Jock]

6 sounds a lot. But I don't have the 100hp.


too much normally has a knock on affect with brake travel


anyone know the proper adjustment ????

So here we have the old subject of "how many clicks should a handbrake have?" - I only chose to quote you Koalar because it was the first one I saw.

I think this whole anomaly has grown up from the old days before self adjusting rear brakes. With a manually adjusted brake, like the old Mini for instance, you would wind the handbrake adjustment off until the cable was slack, then fully adjust the shoes, using the square adjuster on the backplate, until they were just brushing against the drum. Then take up any slack in the handbrake cable until it had a very small amount of slack in it, typically judged by feeling the "clicks" as you pulled the lever up. The number of clicks could vary depending on how fine the ratchet mechanism was but typically, on our BL vehicles, would be around 3, 4 or maybe 5 clicks. So all us "old school" mechanics got used to feeling for around 3 clicks and so the "myth" was born.

Today I can't think of anything I've worked on recently which didn't have self adjusting rear brakes. The important thing with these is to remember that the adjusting mechanisms are (in most cases) worked by the handbrake mechanism - usually on the ratchet principle. For this sort of mechanism to work properly the lever at the brake end (either on the caliper or on one of the brake shoes inside the drum) must be able to return far enough to pick up the next "notch" of the ratchet mechanism.

So, with drum brakes, whether you're fitting new shoes or rebuilding using existing parts, After you've got the whole assembly reinstalled but before you put the drum back on, look at the lever, on the brake shoe, which the cable is connected too. Typically it will have a small, pressed in, stop - but there are other designs - When correctly adjusted the handbrake cable should be slack enough to be just allowing this stop to contact it's rest (which in most cases will be the shoe itself.) I like to take the cable up until there is just a "fag paper" thickness gap which ensures there is no actual slack in the cable. Now put the drum back on - and make sure the drum on the other side is on too! - and pump the brake pedal vigorously a few times to settle the shoes then work the handbrake lever up and down over it's full stroke - if you've backed the self adjusters on the shoes off a long way it could take quite a number of pulls, maybe even 20 or so. This will "set" the adjusters (as long as they are not seized) so that the clearance between the friction face of the shoes and drums is as intended. I usually then go for a few miles drive and come back and whip the drums off just to check if anything needs "fine" adjustment. The big thing - apart from hoping not to see any fluid leaks of course - is to confirm that the levers are still just a smidgeon clear of the stops. If all is Ok then pop the drums and wheels back on and you're done. It's extremely important that the levers are adjusted like this to ensure the ratcheting mechanism can keep the shoes adjusted. Because the levers need to fully return it's not unusual to find the lever in the car will pull up by quite a few clicks, especially if new linings have been fitted. Certainly if you are only getting 2 or 3 clicks your cables are probably too tight and the self adjusters will not work so you will get the brake pedal sinking lower and lower as the linings wear. Don't forget to tighten any lock nuts on the cable adjuster if they are the type with lock nuts!

Disc brakes, although quite different in their operation, have their hand brake cables adjusted in a similar way. After reassembly look at the levers on the calipers. They should be just about touching their stops. If not slacken the cable adjuster until they are positively touching their stops and there's slack in the cable (just a wee bit is fine). Then retighten until both levers just, and only just, pull off their stops. Now pump the pedal a few times and pull the lever in the car up and down over it's full stroke a few times. Most calipers take up slack when the pedal is pressed so you may not need to operate the lever more than a couple of times but some older designs do use the lever to set adjustment. You'll just have to try it. When your pedal feels good go for a few miles drive and use the handbrake every time you stop. Then recheck the levers at the calipers are still just off their stops (and, like the drum levers, we are talking a just barely visible gap here). You're now done.

If you find the gap on one side is bigger than the other, and both levers are clear of their stops, You've probably got a "sticky" cable on the side with the bigger gap.

Incorrectly adjusted handbrake cables are a very very common thing and cause all sorts of brake pedal problems. So many people think that if they have a "slack" hand brake they can sort it by tightening the cable adjuster. If they do that all they are doing is disabling the self adjusters and although the lever will feel better for a while it will rapidly go slack again because they've overridden the self adjusting mechanism. What they should be doing is checking what's gone wrong at the wheel where the brake is.

I suppose I should finish by saying that what I've described here is what I've seen on every car I've worked on in quite a few years now. However car design is diverse so if you're not confident that your brakes work like this then don't fiddle with them 'till you are sure what you're doing - preferably check up in a manual for the vehicle. I have a philosophy toward car repair - They have to go exactly where you point them and stop rapidly in a controlled fashion when needed. If they don't go there very fast that can be annoying but not going where you point them or stopping quickly when necessary can get you and others dead in a hurry!

 

[Wazzzer]

If you like a firm brake pedal, fit HEL braided hoses. 600mm long hoses with four grommets will do each side at the rear with off the shelf Panda dimension hoses at the fronts.
The downside is you cant use a hose clamp while servicing the brakes. I use a bolt through the rear banjo and a cap at the front.

I kinda wished I had bought the braided lines now but I'd spent the best part of £200 on the calipers, cables and standard lines so I had to stop somewhere!

I might add them to the "list"

 

[Pugglt Auld Jock]

I have to say my inclination for a daily driver is to keep everything as near standard as possible because it makes repair and maintenance tasks so easy and predictable. If something goes wrong you can just walk "round the corner" and buy a new one off the shelf and be back on the road in short order.

If the vehicle is "special" and a bit more of a play thing then by all means go as mad as you like!

 

[koalar]

the is on a garage ramp.

slacken handbrake cable by at least three turns
car at idle
forcibly press the brake peddle 15 times
retighten the cable
make sure the rear wheel rotate freely
check the handbrake action starts before the First notch
make sure the handbrake doesn't past the fifth notch
switch of the engine

I would switch off the engine after the 15 times at home.

 

[DaveMcT]

I kinda wished I had bought the braided lines now but I'd spent the best part of £200 on the calipers, cables and standard lines so I had to stop somewhere!

I might add them to the "list"

I went for braided because the hassle at the back with flex/metal flex made a single braided (each side) the easier option for little more cost. I did the fronts to complete the set but could have left them with standard hoses.

 

[Pugglt Auld Jock]

the is on a garage ramp.

slacken handbrake cable by at least three turns
car at idle
forcibly press the brake peddle 15 times
retighten the cable
make sure the rear wheel rotate freely
check the handbrake action starts before the First notch
make sure the handbrake doesn't past the fifth notch
switch of the engine

I would switch off the engine after the 15 times at home.

Hi Koalar. I know you're showing us the "bible's" recommended procedure here and who am I to have the audacity to have a different opinion? However I'm just a little uneasy with the recommendation to "Make a note of the original position of the nut for the handbrake cable adjustment and then slacken it for a few turns to ensure the cable is completely loosened" Ok, I totally agree with this as it should ensure the levers at the hub end are back against their stops - but nowhere does it recommend you check to ensure the levers have actually returned to their stops (I've often seen partially, or totally, seized levers which are not able to return under their own spring action to rest on their stops).

Then it recommends that, with engine idling - I guess this is to enable servo operation - to press the brake pedal forcefully a number of times. Fine with this, it should ensure the adjusters set themselves.

Now for the bit I'm most unhappy with "retighten the handbrake cable adjustment nut to the original position". On a quite new vehicle, assuming the adjustment was correctly set in the first place, this is probably sound. However, especially if the vehicle is not in it's first flush of youth, it does not take into account that someone has incorrectly adjusted the cable before you came along. Crucially though it makes no concession to wear in any of the component parts. It does partially do this by telling you to check that with the handbrake off the wheels rotate freely which might (I only say might though) pick up on a partially seized mechanism. Checking that the braking action starts before the first notch on the ratchet without checking that the levers at the wheel end are fully returned to start with is also a bit pointless don't you think?

Then finally checking that the lever moves through no more than 5 clicks. I'd broadly agree with, providing you have checked that the wheel end levers are fully returning before you start and nothing is seized, except to say that if there is internal wear on the caliper (or drum type shoe adjusting mechanisms) you may get slightly more "pull up" on the handbrake lever as it takes up the worn slack.

The danger, in my possibly ignorant view? is that if you try to follow this guide too rigidly then you might end up, especially on an older vehicle with worn (but serviceable) components, with a cable either completely wrongly adjusted or too tightly adjusted and so rendering the self adjusting mechanism inoperative.

So there you are. For better or worse that's my view. Hope I haven't offended you Koalar? just thought these observations might be of interest and I'd love for you all to pile in and tell me where I'm wrong?

 

[Pugglt Auld Jock]

Just before I break off here I'm thinking about the posts I've made above and although we are talking about a specific set up here I can think of vehicles I've worked on which varied greatly in design from the example we are discussing here. So I suppose it's important to understand how the device you are working on is supposed to work - a manual helps greatly here but common sense needs to be applied too.

As an example, which some of you will be familiar with, how about the rear brakes on our old "Felicity" (Mk1 Panda Parade - the purple one in my avatar photo) They were, are, self adjusting but worked very differently to most I've ever worked on. The backplates had pins fixed solidly to them which protruded on the lining side. Then the brake shoes had top hat section adjusters which fitted loosely over these pins when installed and these adjusters themselves were a loose fit in the holes in the shoes. There was a friction washer either side of the shoe hole which was tensioned by a very strong spring on the "top hat" which gripped the shoe strongly binding the "top hat" to the shoe. When you operated the brake the cylinder would move the shoes apart so they gripped the drum exactly as any other design of drum brake but the "top hat" had only a very small amount of free play on the backplate pin before it went solid and the shoe would be pushed sideways through the friction washers. When you released the brake pedal the return springs would only be able to return the shoes as far as the free play between the top hats and the pins allowed. The return springs were supposed to be too weak to overcome the spring loaded friction washers. As the linings wore the shoes would be pushed further out through the friction washer arrangement but only able to return by the amount of free play on the top hats/pins which gave the running clearance. They worked quite well when new but the friction washers tended to loose their grip on the shoes and the return springs would then tend to pull the shoes too far back so you ended up with a long pedal. The hand brake mechanism consisted of a simple lever pivoted on the trailing shoe and acting, via a pivot pin, on a balance bar which, in turn, pushed on the leading shoe. It worked quite well when in good order but as it wore it became quite inefficient and they were well known for having poor hand brakes. The MOT pass was often pretty marginal. Having owned Felicity for some 20 years I "fiddled" around with this hand brake set up quite a lot trying to sort it out and I found that the problem was twofold:
1. Because the balance bar was a fixed length with no self adjusting mechanism, as the linings wear the lever steadily moved further and further over centre of the ideal position so the force applied to the linings by the handbrake mechanism becomes less as the linings wear.
2) The quite small diameter pivot pin between the balance bar and lever wears - as does it's hole in the lever and balance bar - which considerably increases the over centre positioning of the lever so adding to the reduction in effective leverage.
A bit of a double whammy!

I looked closely at the relationship between the pivot pin and the balance bar (I had several spare ones to experiment with) and remade one by drifting out the pivot pin and then redrilling the holes in the lever and balance bar to take a slightly larger clevis pin so eliminating the slop in the joint. I drilled the hole in the pin and balance bar slightly "off centre" so that the lever, when reinstalled in the backplate with the linings, was "cocked" further back. So the cables had to be slackened a bit to refit them and the lever was "cocked"considerably before it's over centre position (don't think I've described that very well? but the effect was to increase the length of the balance bar to pin centre length, if you get me?) This simple mod completely transformed the hand brake efficiency. The garage wanted to know what I'd done next time they MOT'd her as they'd never seen one with such a good hand brake performance. I was positively blushing!

This vehicle is also one of the few more modern I've worked with where, due to the fixed length of the balance bar, the hand brake cable had to be adjusted (shortened) as the linings wore. In fact you could use this to compensate for the - often - inoperative self adjusting friction washers by the simple expedient of taking the play up with the hand brake cables which forced the linings out. Not many I can think of where you can do that. So, perhaps you can see that this setup obays almost none of the rules we have been previously discussing.

 

[Pugglt Auld Jock]

Here's a picture of some spare shoes I still have for Felicity which clearly shows the spring loaded "top hats" and friction washer arrangement:



The friction washers, made from a kind of fibre, are "hiding" under the big dished washers which the springs are pushing on. There are friction washers on the other side of the shoe too.

 

[koalar]

you can offend me

everyone is entitled to their opinion

the OP was complaining the brake peddle was long

I have two Pandas. Although drum rears. When swapping from car to car it took a bit of mental adjustment as one had a longer brake peddle than the other.

After adjusting the handbrake both now feel the same and the one that had the long peddle also feels firmer although this is probably more a psychological affect.

Hence I asked if 6 click was correct for the disc brake version and what was the correct adjustment. As 3 or 4 is the norm for drum brakes. I Thought someone that had serviced a disc version should have chimed up. But it appears that 3 or 4 is the norm for the disc also.