I mentioned in a post somewhere - can't find it though - That my youngest boy's wife was paying us a visit yesterday. This was partly so she and Mrs Jock could talk babies and various preparations which are under consideration for the imminent arrival of our new grandchild, but also so I could investigate a possible partly seized front brake on the Jazz.

I'd parked my car in the road so she was able to pull straight onto my hard standing in front of the house. Ah, so it'll be the N/S/F brake you're talking about to judge from the substantial "whisp" of smoke curling gently up from it? While it was cooling down I gave the other three a check over. Rears look OK although the discs have seen better days. They will need pads at the next service so I'll factor in discs too. O/S/F pads are about 3/4 worn and the discs are still nice and shiny but not in their first flush of youth (probably renewed with the last pad change) The wheel spins by hand but there is just a touch more drag than I would expect.

So, now for the main event. Wheel nuts slackened on N/S/F wheel (nuts and studs for a change) and car jacked up with stand under chassis. Pads look 3/4 worn - just - like the O/S so, with a bit if luck it's not been running like this for long. Things have been getting very hot though with slight bluing on the disc and a lot of heat still in the assembly, note to self, keep an eye on the wheel bearing seal. I can turn the wheel but would not say it can be "spun" - there's a lot of drag. Ok, wheel nuts off and wheel removed, turn steering fully to port, undo the caliper retaining set screws - 12mm spanner? Honda doing it differently again! and the caliper is solid. I can't retract the piston at all. Levering with screwdrivers, tyre lever etc achieves nothing. I finally managed with a large G clamp with one end on the outer pad and the other on the inside of the caliper. I got the piston pushed back enough to get the caliper off the carrier. Pads were free in carrier so it's definitely the caliper itself at fault.

At this point a garage would just order up and fit a new caliper but I decided to examine the caliper closely to see if it would take an overhaul kit. I got Mrs J to pump the brake pedal expecting the piston to be jacked out of the caliper but NO! Mrs J couldn't/was reluctant to stand on the pedal hard enough to shift the piston (at this point I knew I was probably on a looser but continued anyway). I found I had to run the engine, so I had the servo assist, before I could get the piston shifted. Once it was on the move it went quite easily and after about 8 pumps (1/2 to 3/4 depression only to try to avoid M/Cyl problems) I topped the reservoir to max and kept on going until the piston popped out. Clamped up the flex hose and drained the, now open, caliper into a tin. Oh dear this looks rusty although the bore deeper in looks good so it might all clean up with some emery? Now for the piston. Oh well, game over. Here's the piston after being cleaned up:



Even after a bit of a clean up with some fine emery It's obvious the corrosion has penetrated the plating (is it chrome?). If I'm to rescue this caliper it's going to need a new piston, fluid and dust seals etc and a fair bit of derusting and gunge busting of the caliper casting. This sort of kit is not usually on the shelves at your local factor or the likes of Halfords as a quick 'phone call confirms. "I've got a rebuilt caliper kit on the shelf right now though if you want" offered my factor. The price was reasonable and £18 back if the old caliper is acceptable. Who judges if it's acceptable I ask? That's me he says! Done, I'll be right round.

The new caliper is remanufactured by Apec (I've had their pads before and they've been fine) It's a quality bit of kit complete with a wee sachet of brake grease, new bleed nipple, new rubber bellows for the guide pins and sealing washers for the banjo connector on the flex hose. Time's getting on now - she didn't turn up with the car until lunch time - so a quick clean up, glaze bust on the pads and a wee bit brake grease in the right places sees the caliper reinstalled (a couple of new retaining screws would have been nice) and the banjo fixing tightened into place with it's new sealing crush washers. What a good idea a banjo fitting is on the caliper end of the flex. Here's the new caliper after fitting, you can clearly see the banjo union (I didn't take any pictures as I worked because brake fluid on the camera is just not worth thinking about!)



How often have you fitted a new caliper only to find that the old screw in flex hose, once fully tightened, has a twist in it? To rectify this you've got to slacken the tube nut and chassis fixing on the other end of the flex to allow it to be rotated to "loose" the twist. Good luck with that if the car is more than a few years old!

Now to bleed it out and I'm done Whoo hoo! Ok Mrs Jock, just jump in there and pump the pedal when I say (Daughter in law is 8 months pregnant and just getting behind the wheel is effort enough!) Ok, nipple slackened and push down, Nipple tightened and pedal up. Repeat several times. No fluid appearing? Oh dear! Maybe the nipple needs more than 3/4 of a turn so slacken it a couple of turns and Mrs J pumps again. Still no fluid going down the "bleeding" tube! What the? but wait a minute, there's fluid oozing out past the bleed nipple threads? that's weird? Took the nipple out (knowing what I'm going to find as this is not the first time I've had this) and guess what? the long axial drilling - down the length of the nipple - is drilled right to it's depth but the wee cross hole near the end is not drilled in far enough to meet up with the axial hole so the fluid has no way out. Luckily I slaistered copaslip all over the nipple on the old caliper when I did a fluid renewal a couple of years ago so it came out easily and once installed in the new caliper the bleeding was quickly completed. Usually I would do this with my Gunson pressure bleeder but the Honda master cylinder has a "funny" top and I don't have an adaptor to fit (must buy a universal one)

I had checked very roughly for disc run out with a screwdriver clamped to my axle stand - in the same way I check for wheel run out before doing toe adjustments. It's not very accurate to do it this way, you really need a dial gauge, but it gives a rough indication if there's a serious problem. (A badly overheated disc may well be warped) My rough and ready check had not shown up any problems and I was relieved to find there were no obvious problems on road test. In the not too distant future a decision will need to be made over the other front caliper which is probably slightly "sick" at this time and a set of front pads. Maybe the O/S/F caliper will soon become more of a problem and make that decision for us. Rear pads and discs, whilst not a priority, will be needed in the medium term future. (hope the calipers wind back ok!

As I was finally topping up the brake fluid I noticed the strut top mounts had nice little flexible plastic (maybe silicon rubber of some sort?) boots to keep them clean.



This car is more than 2 years older than our Panda but the threads under these boots - I took one off for a look - are absolutely pristine. What a good idea! The more I work on this car the more I like all these little touches. Still regret not buying that Civic Estate!

Daughter in law, and grandchild soon to be, departed and I roughly reassembled the piston and seals into the old caliper, jumped in the Panda (Becky) and shot round to the factors with maybe 10 minutes 'till they closed. £18, as stated, refunded onto my card and they commented that I shouldn't have bothered to do such a good job of cleaning up the old caliper! Unfortunately they were very busy so I wasn't able to do much leg pulling over the duff bleed nipple, I'll save that for next time.

My Brother has a Jazz. One back brake piston was seized so badly he had to get a new caliper. How he could not feel the lack of braking I don't know.

Aye Dave, as anyone who has read other brake related stuff I've posted will know, I'm not a great fan of disc brakes on rear wheels. I will concede that they have a place on high performance vehicles but for your everyday run around I really don't like them. In terms of braking performance drums are very adequate for rear brakes (considering front brakes actually do most of the "stopping" for you). In my experience discs on the rear corrode more rapidly, probably because they are not getting as hot as the fronts and live being bombarded with all the water, salt, road grit etc, etc being thrown up by the front wheels - Drum shoes and their friction facings are, by their very design, protected. With some exceptions discs also seem to be less good at being Handbrakes and the kerfuffle involved in winding the piston back when new pads are needed is just "silly". There's also the cost of sorting them out when they leak/corrode. A drum brake cylinder being several times cheaper than a caliper.

Jock is spot on about rear disc brakes, but on the 100HP and the Punto HGT I used to drive the rear discs were not really a problem. The discs and pads are dirt cheap anyway - same as fronts on "lesser" Fiats.

Discs are used because they work properly with ABS. The short pad movement allows rapid pulsing. Drums cannot respond fast enough so ABS systems on drum braked cars just reduce the power fed to the back wheels. Disc brakes really are safer in bad conditions.

DaveMcT said:

Discs are used because they work properly with ABS. The short pad movement allows rapid pulsing. Drums cannot respond fast enough so ABS systems on drum braked cars just reduce the power fed to the back wheels. Disc brakes really are safer in bad conditions.

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See, I've said it before, what a wealth of info there is on this forum! After all the years I've spent working on cars, both to earn my living and as my main hobby, I've never thought about that (see above). Of course there was no such thing as ABS when I learned my trade but if it (the way ABS operates with disc vs drums) was ever mentioned on the many training courses I've attended during my working life, it obviously didn't make much of an impression! Thanks for that Dave.

No worries Jock. It's one of those things we never think about but ABS is all about rapid pulsing the brake. The tyre needs time to grip and slip just enough before its released and repeated. I believe that braided hoses improve the effectiveness of ABS as there is less "slack" in the hydraulic system.
I've grown to really like the harder pedal feel on the 100HP which has HEL hoses all round. At first I was worried the hoses were a mistake, but remembered how the old Citroen power brakes used to feel.

DaveMcT said:

I've grown to really like the harder pedal feel on the 100HP which has HEL hoses all round. At first I was worried the hoses were a mistake, but remembered how the old Citroen power brakes used to feel.

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Oh yes, I remember virtually standing the first DS I ever drove on it's nose! that "button" of a brake pedal was very weird with almost no "give" in it wasn't it? I also drove a GS once but don't remember how the brakes felt on it. What I remember most about the GS was the horrendous backlash/snatch in the gearbox when trying to dribble along in traffic with the engine at little more than an idle and clutch fully engaged. It felt a bit like severely worn engine mounts - talk about Kangaroo petrol!

I had a BX1.9 GT with the 105bhp Peugeot twin choke carb engine. Discs all round with super light pedal action, super light hydraulic steering and and that wonderful floaty suspension that still handled amazingly well. The later GTI had 125bhp and ABS brakes.

One brake disc developed a vibration which felt just like ABS through the pedal. It was then that I realised the powered hydraulics actually gave a great brake pedal feel. Something that's entirely lost with vacuum servo brakes.

The mineral oil hydraulic system meant no need to change the brake fluid and I'm told brake bleeding was easier but never did the job myself.

DaveMcT said:

The mineral oil hydraulic system meant no need to change the brake fluid and I'm told brake bleeding was easier but never did the job myself.

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I never worked on the bigger Citroens much although I did mess about quite a bit with the Dyane and 2cv. I would imagine that the bleeding was easier on these bigger cars because the whole system was pump pressurized so all you need to do to bleed it is open a bleed nipple? Lots of "wierd stuff" going on though, like load leveling valves and suspension gas spheres (which became degassed and had to be changed) The give away was that the ride became almost solid when the gas leaked away. I remember being absolutely amazed to see a plaque under the bonnet of one of the very few Rolls Royces I've ever touched which declared that elements of the suspension system were under licence to Citroen! Right enough, when you looked closer there were the same green gas spheres you would see on the top of a Citroen strut!

Well, Daughter in law rang at about 08.30 this morning, just as I was cooking my porridge - yes really - to say that she thought getting the rear brakes (especially the hand brake which isn't holding on anything worthy of the description "hill") sorted out before the new baby arrives would be good. Come right round said I. She was here about 10.00! Actually not bad considering the distance and morning traffic.
I'm not doing a "how to change pads and discs" here, just mentioning some of the more interesting things that came up. I started on the N/S and had no more than the usual agro undoing 11 year old fixings. The caliper pulled back nicely from the carrier - a good indication that the piston/handbrake mechanism is not seized. Honda do choose some weird bolt sizes thought - 12mm and 14mm spanners much in demand? The piston wound back nice and easily (hose clamped off and bleed nipple opened) and I stuck the caliper on an axle stand to save straining the hose:



I was surprised that the pads had to be levered out with a big screwdriver - I put Cera Tec on them last big service. Carrier bolts were very tight but once "cracked" came away easily allowing the carrier itself to be put to one side so I can remove the disc itself.

This was the first real challenge, The little securing screws were not for budging! I tried my impact driver - No luck. This problem is one I've run into before and I was shown how to "sort" it many years ago, when a callow youth, by one of the "old salts"in the workshop. You need 2 centre punches. A nice sharp pointy one and a blunt one with a slightly rounded end. Take the sharp one and put it's tip just in from the edge of the screw at about 45 degrees so that it faces in the direction the screw undoes:



Hit it a few times until it makes a small indentation and raises a small "ridge" of metal in front of the tip. Sometimes this will be enough and the screw will suddenly move but if it doesn't change to the blunt punch because the sharp one will go on cutting into the screw. The blunt one will allow more force to be converted into turning the screw and either it will move or shear. If it shears don't panic, you can actually do without them, they do nothing except stop the disc "flapping about" on the hub when the wheel is not there. If the screw comes out it'll probably look something like this and need a couple of strokes with a file just to clean it up (or buy new ones):



The disc should now come off - often they'll just about fall off but they can be absolutely stuck fast. If stuck some discs will have threaded holes which you can use to jack them off with a couple of bolts but more often you'll just have to get violent with a hammer! I like to use a plastic or leather faced one to reduce the impact felt by the wheel bearing races. After a really thorough clean up of the hub face - so the disc will run "true" to the hub dirt or corrosion here will make the disc "wobble" - a little copa slip (anti seize) on the hub especially where it locates on at the centre and around the very edge of the hub because this is where rust buildup will make it difficult to remove in future:




You can see how the new disc locates:



Putting it all back together was pretty uneventful. I resisted tightening those retaining screws too tightly, maybe I'll benefit one day? So here it is all ready for the road:



Now for the other side. Right away I suspected problems. The fixings were very much like the other side to undo but the caliper didn't want to come off the pads. Quite a lot of hefty levering with big screwdrivers was needed. Once off I did manager to wind the piston back but it took a short length of pipe on the tommy bar to do it. This type of caliper should wind back fairly easily. Needing the length of pipe was screaming to me that the caliper was in distress! However I did get the piston to fully retract so I carried on doing the disc change etc just like the other side. The caliper went back on to the new pads just fine and I thought I'd finished.

Wheels back on, pedal took a couple of pumps to bring the pistons out and worked the handbrake up and down a few times to make sure all the "slack" has been taken up - I'd aready checked the cables were free running and in reasonable condition. A wee drive round the block and back. Jack her up again and the N/S is nice and free spinning with the H/brake off. O/S? Oh dear, a very noticeable drag. Certainly not spinning freely. Yes the cable is allowing the lever to fully return to it's stop. Take the caliper off again and it's still very hard to retract the piston. Now I'm back in the same position I was in with the front caliper. Maybe it would rebuild? But there's only about an hour and she'll need to be on the road back out of town to collect the wee one. Rang the factor. Yes he's got a rebuilt caliper on the shelf (surprisingly, as it's got all the handbrake gubbins, it's a wee bit cheaper than the front caliper!?). Fine, I'm on my way.

Changing over the calipers requires the handbrake cable bracket to be swapped over. The two securing bolts/set screws looked like trouble. (I'll do another post about that because it was the first time I tried a new tool I've bought.) Anyway the change over went well (thank you Honda for that Banjo fitting again) and after building it back together again it bled out nicely (good bleed nipple this time) and behaved as it should when spun.

I was going to do a complete fluid flush but just completely ran out of time. Actually the fluid I was bleeding out looked pretty clear and light colored so I'm happy to let it wait 'till I can get my hands on it again.

On my road test the foot brake felt very good indeed but when I went round the corner to where there is a bit of a hill, although there is an improvement in the handbrake "hold" it's not as good as I would have liked. I've warned her about this and we're going to let her (the Jazz) run for a week or so and see if, as I expect, it improves with the pads bedding in.

Now to reveal my "dirty little secret" I've been hiding from you. I've been keeping "shtum" about it because I wasn't quite sure if I'd wasted my money (in which case I would have just not bothered to mention it!)

Anyone who has read my past posts may have picked up on the Vibroshock tool I expressed interest in? Well I bought one! I don't tend to go in for "gimmicky" tools and, although it looked good in the videos I saw and the research I conducted, I couldn't find anyone who could offer me a demo. There seem to be two main contenders Welzh Werkzeug - a British company based in Gretna (really, with that name? Well yes.) and CTA, an American company. I don't think there's anything between them and I would have bought either but then I realized CTA list all the constituent components separately for replacements but I don't think Welzh do? Then I noticed the CTA seems to be sold under a number of different brand names and in many countries. Seems to me to be a much bigger deal? In the end a fairly local, to me, MAC Tools van franchisee sold me a Powerhand branded version of it.





Then I discovered that whilst the .401 drift is a standard size and fits my air hammer the shank is of a larger diameter than a standard chisel and needs a quick change chuck to be safely retained.

https://www.ebay.co.uk/i/1738688904...91uELMjyEf1OFu-Vpo3JeLm_3-fmlPGEaAgA3EALw_wcB

It took me a wee bit of time to find out about this chuck (in fact there's one sitting on "click and collect" at our local Argos which I'm picking up tomorrow) So, until today, I hadn't yet used the tool - being worried the .401 drift might be "shot" out of the gun!
Of course, wouldn't you believe it, The Welzh has just appeared on ebay at a discount. No boy, just suck it up!

https://www.ebay.co.uk/itm/WELZH-WE...ation-Impact-Socket-Kit-4093-WW-/173618010134

Then today I had to get the handbrake cable bracket off the old caliper on the Jazz. It's held on by two substantial set screws with 12mm (good old Honda, they'd be 13mm on any other brand) hex heads. The cable itself is in the way so I tried a combination spanner first but it was obviously going to round. Then I tried one of my new Bergen Xi-on anti rounding off sockets. By golly it gripped but The fixing was going to snap if I lent on it any harder. These are steel set screws (bolts to some people) screwed into an aluminium casting to a good depth so plenty of opportunity for electrolytic corrosion and they've probably been there for the whole 11 years of the car's life.

This is just exactly what the Vibroshock is intended for. But, oh dear, the chuck isn't here yet! Oh sod it, I'm going to try it without the retainer. As long as I keep the socket on the bolt it can't go anywhere can it? I set my air regulator to 50psi to start with because I didn't want to be too violent at first. Stuck the special 12mm socket on the drift - see how shallow the hex is so that the force is transfered to the bolt not the casting:



Here's how it all goes together:





So I stuck the drift in the gun. Located the socket on the bolt head and gripped the wrench handle, with some trepidation and with a great sense of excitement, pulled the trigger gently (my gun has a proportional trigger so you can control it with the trigger) At first it just rattled away gently to itself with me applying moderate force to the wrench handle. The bolt didn't move but the idea is to let it "rattle" for a wee while to disturb the corrosion and loosen the threads. As not much was happening (by the way I'd soaked it with plus gas before starting - they recommend using any releasing fluid) I pulled the trigger almost fully and the gun really really got down to work - quite satisfying and very noisy. Within about 5 to 10 seconds the bolt started to yield to my pressure on the wrench handle and after about one full turn it came out with a ratchet and socket. The second bolt moved much quicker because I didn't muck about on a low power setting, just "wellied" into it from the start. The big thing is to let it rattle 'till the bolt can be turned with only moderate force on the wrench thus avoiding snapping it.

So, early days yet but I'm very very pleased with my new tool and can see it being used often on bleed nipples and the like - who knows where this might end?

Just realized, if you look at the picture of the caliper resting on the axle stand, you can see the threaded ends of the two bolts which hold the handbrake bracket to the caliper:



Gives some idea of the corrosion on the threads but not what was inside the casting.

When I removed my 100HP rear wheel spindles from the swing arms at least two studs unscrewed about 360 degrees then went solid as the gunked up threads jammed the threads. One unscrewed the stud itself. The other stripped the threads causing the nut to spin and not go in or out. It had to be arc welded but at least that heat shocked the threads so the stud came out.

My point is that dirty threads (even wire brushed and penetrating oiled) will probably let you down. If its a bolt into a closed end hole, then it's usually ok. If the back end thread is open you can expect a miserable day of toil and trouble.

DaveMcT said:

When I removed my 100HP rear wheel spindles from the swing arms at least two studs unscrewed about 360 degrees then went solid as the gunked up threads jammed the threads. One unscrewed the stud itself. The other stripped the threads causing the nut to spin and not go in or out. It had to be arc welded but at least that heat shocked the threads so the stud came out.

My point is that dirty threads (even wire brushed and penetrating oiled) will probably let you down. If its a bolt into a closed end hole, then it's usually ok. If the back end thread is open you can expect a miserable day of toil and trouble.

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Absolutely Dave. If you look at the pic of the caliper resting on the axle stand you'll see that's exactly the situation. There was about one and a half turns before the end of the bolt went flush with the casting and it looked really crusty. I wasn't expecting them to come out easily. Maybe it was the Vibro tool, maybe not. Time and a few more tryouts before I'm convinced? Although I think this Vibro thing is pretty good there's always going to be need for the welding torch and other solutions though. In extreme situations I don't think it can "hold a torch" (sorry) to the heat of the arc.