Peugeot 106 Rallye | NEED HELP! Unbehaving brakes!

4 years ago I got this gem back on the road.. and now its time for another MOT... Some rust repairs where made, but it turns out the getting the rear brakes to work good enough is a challenge I was NOT expecting!
#Rallye #peugoet #gti
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[@Charlie1012000]

Investigate different brake shoe friction line materials. They come with different friction coefficients.

[@johnmcdonnell81]

As it's a brake problem I'd change the master cylinder regardless. It a good place to start.

[@JasperV70-205CT-BX]

Really pretty car! A bit frustrating youre not able to pinpoint the problem yet, but perhaps the master is the next step?

[@jeremytoms5163]

Couple of things. Check the brake shoes are adjusted to get them as close as possible. Check the shoes aren’t glazed over, if they’re shiny then they won’t grip during braking, Citroen AX had exactly that problem. I used to scuff them up with a wire wheel and wash them with petrol to make them as rough and clean as possible. Check the make of the shoes, abs cars have a harder compound as there’s more braking force. Hope you get to the bottom of this, they’re of a time when hatchbacks were fun to drive, new ones are too safe and steady with the fun dialled out.

[@ShaunMurray63]

Good to see the 106 again. Probably going to be a master cylinder/servo problem or maybe brake pipes that for some reason pinch somehow and the internal diameter of the pipe/pipes has been reduced , but I am suspecting servo/master cylinder problem.

[@twocvbloke]

Could be a collapsed flexi or a blockage somewhere, possibly even an issue with the mater cylinder, just got to play around and find out... :)

[@kevinnye5132]

Not worried at all about the movement of rear of car Seppo because I’m not the one under there 😂. Yes I agree is important to know why something fails and all a learning experience, Peugeot is in great condition though so must have done a good job 4 years ago 👌🏻

[@zaneclone]

I'd be looking at the master... beyond that, the rear flexi's- they may have collapsed internally...

[@robertngreen6]

Yeah - SO many test drives LOL! 😂

[@SeasideGarage]

many many many... I love the 106

[@W555LAN]

as an example in the Uk there are guidance documents related to emissions testing procedure specifically related to the non standard fast idle speed which is normally around 2,500RPM - required for particular manufacturers. I know this as my car incorrectly failed the MOT because the garage could not maintain the standard idle speed due to the design of the idle speed control valve. The MOT garage incorrectly failed the car and I had to show them the document as they were incompetent and not aware of such document which stated the engine was to be run at 3,500RPM. The reason for the long winded preamble is there may be such equivalent document in your country related to non standard rear braking efficiency for certain car manufacturers that the MOT station must observe….

[@jfv65]

- Is the master brake cylinder actually the correct one for the car? It needs to have the correct spec to be able to displace the correct amount of fluid. - maybe you can use a master cylinder from the Citroen Saxo models? Or the newer Peu106 models? Or 205 Rallye?

[@theblackhand6485]

If the brake testing bench for both wheels were the same brake force I would not worry. If one side is braking more or less to the opposite then you have a problem. First of all a would bleed all 4 lines. Starting rear right and then a cross. Thus front left etc. Simply because, as you said, it is at least two years ago the fluid was changed. And did you actually change it you may wonder? Braking fluid is hygroscopic. It attracts water. So this together with air bubbles are not favorable. Bleed all out, put fresh in. Commenters already mentioned: check the surface of the brake lads. Glazed means cleaning up with sandpaper etc. Are they the right ones? May be smart that the owner bring you a technical handbook or does some surfing on the web aka forums.

[@scottishcontentcreators]

Master cylinder seals allowing fluid past them? Can you get a seal kit? Has the car had a replacement axle at any point in its life, I know French cars like a back axle now and again, could be a wrong set up? I would have checked the old fluid carefully for any debris from the inside of a hose collapsing but the fluid looked nice as it bled out? If it persists to give bad braking force at the rear, get a rally car brake bias adjuster and throw those restrictor valve cylinders away?

[@rustyrover3808]

Being a meddler I would look at the restrictor on the old cylinders and see if it was possible to open up the orifice b6y a small amount to see if it worked, could it be different brake fluid with different compression rates ?

[@tiitsaul9036]

That's a strange master sylinder setup. I'd hate to do an emergency stop on an highway with half brake failure. Either it will pull into ditch or into oncoming traffic.

[@kosir1234]

lots of cars have diagonally separated brakes, better to loose 1 front brake than 2. And diagonally is so it swerves less when you brake.

[@jochenstacker7448]

It's a very common design feature that will prevent you from losing all your brakes instead of just half your brakes. This only becomes relevant in case of total failure of your brake master cylinder. So more relevant to the US because of the state of the cars over there.

[@christianchristiansen99]

Can the MOT place measure the braking force of the handbrake? If so, you’d be able to compare it to the braking force of the hydraulic brake system. If you’re able to apply more rear axle braking force through the handbrake, you can turn your attention to the brake lines/flex lines. From what you described, the right/left brake action on the rear axle is similar, so probably not a kinked/pinched line, but the internal diameter could be wrong. Good luck - very interested to see how this turns out. I was honestly a bit surprised to see you change the brake cylinders when nothing pointed to them being the issue, that’s very un-seaside garage ;) Although I can certainly appreciate that it would have been an easy/cheap fix.

[@SeasideGarage]

Yea the handbrake gave around a 100kg

[@rodneyperkins1057]

As some others have suggested the rear brake compensation valve may be seized or missing springs, possibility not set correctly.

[@SeasideGarage]

There is none on the rallye

[@rodneyperkins1057]

@@SeasideGarage is there a brake proportion valve in the front to back fluid line? Or tandem master cylinder with separate lines for front and rear? Have you a pressure bleeder, if you have you can check at the rear bleed valves how much pressure and fluid comes out around 5psi. Sorry if you have already tried this. I know it was a common problem on the 205 proportion valve, just cannot remember if rallye had one. Best of luck.

[@simonprime5541]

All I can think is brake shoe adjustment - looks like they are self adjusting but are they actually doing so ?(do the shoes look like they are in contact all they way around? ) I'm sure you have checked the hinge areas for corrosion / free movement? Good luck. !!

[@SeasideGarage]

Thanks... it was adjustment related... :)

[@TheGibby3340]

Is it possible the internal restrictor within the wheel cylinders are trapping air that a standard on car bleed may not remove? Perhaps bench filling and pre-bleeding the wheel cylinders in multiple orientations may help. Unlikely since you pressure bled, just a thought. 🤔 🍻🍀

[@SeasideGarage]

Good point... but its not that... new video out... ;)

[@dylan3657]

strange one, if the shoes and pads are as close as they can be and the pedal is firm and thats the best brake force it can get 50? i would put regular brake cylinders on and fit a brake limiter/proporsional valve block into the lines

[@AntonioToma-q2j]

Hej. Is there an on-line Peugeot forum / owners club that might be able to offer advice? Another excellent episode. Thank you.

[@mortenwad1938]

Hvis den bremser lige på baghjulene er det ikke ude ved hjulene. Er du sikker på der ikke sidder en ventil på rørene der går bagud oppe ved hovedcylinderen? Det gør der på mange af de andre ældre Peugeot modeller. Jeg tror ikke du skal forvente at de trække bagenden ned når du bremser hårdt på tør asfalt men det skal kunne lave spor ved hård opbremsning på en løs grusvej.

[@MrToxicSkittle]

Just another thought: if the pressure regulation happens inside the wheel cylinder, the brake pressure should be the same in the front and rear brake lines, right? So maybe you can measure the brake fluid pressure front and rear to see if they are identical?

[@chrissmith7655]

Hi,if the master has a pipe for front and one for back, are they in correct oulet on master?

[@henryv.582]

There shall be brake pressure regulator above rear axel ? Looks like junction box, and all brake lines goes thrue it. If car has not driven much lately those might get jummed.

[@SeasideGarage]

Nope.. not on the rallye...

[@v12mike30]

Is it possible for the right and left wheel cylinders to be swapped? The leading and trailing shoes zeem to have different forces applied.

[@SeasideGarage]

I was hopping for that... but no... it would have made sooo much sense

[@paulconnelly8369]

it could also be a bad vacume unit i has this a few times my self

[@orionpitman3369]

HI just a throw at the wall. Have you got lots of weight lying around the work shop if so fill the boot and then test drive the car and test the car at the test station again just a thought it's time consuming but it's free all the best.

[@MrToxicSkittle]

I have had a similar issue with my mini. But the error was the the wheel cylinder piston diameter was too small. My point is your pressure may be ok, but maybe the piston diameter is too small? The brake force is governed by the brake fluid pressure multiplied by the surface area of the wheel cylinder piston. You sounded quite confident when you said is was 19/19.1 mm, but even going a few mm up will increase the brake force significantly. 20% larger diameter will give 44% more brake force. I don’t know if a larger wheel cylinder exists for the 106, but IF you have options, it could be the culprit!

[@SeasideGarage]

Only two cylinders available... abs and non abs..

[@RCoster47]

So, does the MOT have the same minimum value for rear braking, regardless of the car's weight and proportions? I mean, you would expect it to be higher on some 3 ton large SUV, than on super light 3-door hatchback...

[@fulf]

In live Sweden i never heard minimum brake force. What i know we have is maximum 30% difference on each axel.

[@mikkarin1]

Did you change the proportioning valve and grease up any connections?😊

[@SeasideGarage]

No valve on the rallye

[@andrewmooreandrewrmoore7615]

Take the spare tyre out and replace it with a bag of sand or cement before MOT

[@SeasideGarage]

There is no valve that senses weight on the rallye... its the same pressure not matter the luggage or cement.... :)

[@dodgydruid]

Look to see if there is something called a "brake bias valve" which puts most the braking force into the front discs and less braking force into the rear drums. A clogged or broken one of those would replicate your issue completely. They usually are on all disc setups but they have found their way onto disc/drum rigs over the years. The only other thing is check flexi's for ballooning and check hard lines for any sort of crimping damage which restricts flow. Ballooning steals some of the pressure to balloon before the fluid is allowed to travel forward, its very hard to catch ballooning as it can be a simple small bulge to a series of bulges in one flexi. Might consider "Newfren'ing" the shoes by with a dremel grinding in a diagonal series of cuts that don't go through the whole shoe, it stops brake fade on hot brake shoes as it allows the heat to dissipate, for brake liner dust to be able to escape and creates a minor fan action of cooler air.

[@leighton757]

Flexable hoses. maybe

[@richardsawtell256]

is the shoe radius correct to the drum? and check the line pressure which will tell you what the master is doing

[@frankandersstuen1464]

best answere. shoe need to be grinded to fit drum or fit new drums.will not get correct otherwise

[@richardsawtell256]

@@frankandersstuen1464 we have a lot of issues with drum brakes with bad radius where the shoe doesnt contact the drum correctly and causes imbalance , new shoes and drums should be close but i have seen after market shoes way off and only touch in the middle of the shoe , adjustment only affects pedal height not braking force

[@legless1956]

Is it really a problem? it's just to stop the rear overtaking the front.

[@SeasideGarage]

well.. it will be illegal to use on the road...

[@oggy4418]

Hi, me again 😅As you know I have the same problem with the rear breaks being really week. I think that is still possible there is some air in the wheel cylinder. If you look at 5:07 the bleeding screw is noticeable lower than the highest point and I noticed today that even if the car is on the ground, the wheel cylinder is not horizontally with the ground. It is under angle with the bleeding screw being lower than the highest point. Could that be the problem? I´ve already check other pictures and videos and some was mounted the different way when the bleeding screw is at the highest point🤷‍♂ But I don't know because on the other hand the one piece which moves out with the integrated pressure regulator is much longer than the other and if it is push all the way in it fills up all the space and there is also an O-ring sealing and basically the whole thing is reaching all the way down to the bleand screw but :D if it is push out it's a different story and there could be some air left in the section which is higher than the bleeding screw...

[@SeasideGarage]

I dont think its the bleed screw no... its bleed under pressure and air in the system is very feelable...

[@oggy4418]

@@SeasideGarage I just checked the pictures in Haynes Service Manual which I forgot and it's like we have it so I guess it's all right. Today I did exactly what you did again without any problem or overheating and the rear breaks noticeble better. I can't spin the wheels by hand like before it's very hard while pushing break pedal and them being off the ground. 👍

[@SeasideGarage]

@@oggy4418 sounds good!

[@oggy4418]

@@SeasideGarage I'm after break test. The rear not breaking still. I will change the flex hoses but other than that I don't know what to do. The master cylinder is the last chance. I order break pressure test kit to be sure where is the problem exactly.

[@SeasideGarage]

@@oggy4418 damn 106 brakes

[@Frenchcrop]

Probably

[@TheBTG88]

What’s happening with the Saab?

[@SeasideGarage]

It's in the barn until it behaves ! I need to decide on what to do about the paint job... :)

[@rimmersbryggeri]

I would guess it has a brake proportioning system on the rear axle and that is probably seized. On the 206 the unit is on the right side of the car. There are videos abouth changing the rear axle bearings where it is clearly shown. If it tdoesnt work to fully slacken the handbrake cables, then set the shoes, the re tighten the handbrake cables so that there are the right amount of clicks on the lever then there is probably something wrong with the proportioning unit or the assemblage of the springs in the drums. The self adjustors may also be seized. The proportioning thing I believe is there so that the brakes are stronger if the car is loaded.