NSR Brake Locked on after Bump in Road

[Pug_XUD_KeenAmateur]

My N/S/R Brake locked on after I went over a slight pot-hole. It’s a Drum brake on a 405 estate.

It locked on for approx 3 or 4 seconds and brought me to a swift stop from about 25mph, with a severe smell of burning rubber from the affected tyre, I’m pretty sure that the O/S did not lock up, hence the slight swerve caused. By the time I’d stopped it had righted itself.

Obviously, I’ve investigated as far as possible and considered the possibilities so some details.

Brake fluid level is fine, there’s no loss of fluid and no tell-tale on the backplate

When I yank the handbrake on hard it brings me to a swift and evenly balanced (left/right) stop

I noted that the handbrake cable was less slack on the N/S with the handbrake off than it was on the O/S even though that seems surprising, given the flexible nature of the join in the middle of the car. So perhaps a bit of a clue.

I’ve been in the habit for some time now of parking the car in gear with the handbrake off and had used the brakes lightly a couple of times to negotiate two junctions in the few hundred yards I’d travelled since setting off. All was normal.

I had one front seat passenger and an empty boot; ie unladen. Its laden quite often for an old car and I always feel the Load Sensing valve doing its job putting greater brake bias on the rear axle, most recently on a heavily laden 25mile outward journey the previous day with all of my Step-Son’s worldly goods. The return journey of the same length was unladen, all was normal and I could tell that the brake bias was back to its normal unladen ‘front bias’. I replaced the Spring on the LSR a couple of years ago.

I replaced the rear brake shoes about 1,000miles ago and intended also replacing the wheel cylinders as a matter of course, but sourced the incorrect type so didn’t. The front Discs & Pads were replaced just prior to the rears. The brakes clearly are not ABS and the car’s sufficiently old not to have an ECU.

Anyone else had this happen? In a nutshell it seems that the suspension travel of a not very big pot-hole has triggered the rear brake somewhat fiercely on that wheel only.

[RichardW]

It's probably de-laminated the friction material from the shoe and it jammed in somewhere. I'd get the drum off and have a good look at it.

[Pug_XUD_KeenAmateur]

Feasible suggestion Richard, thank you, but just had the Drum off and not the case here. All appears fine.

(would upload a photo, but don't think I've got the necessary priveleges to do so).

Thanks though.

[myglaren]

Anyone can post photo's and it is encouraged, makes things much clearer for the most part.

There's a thread here to make the procedure clear.

[Pug_XUD_KeenAmateur]

Thanks myglaren, gonna sort that soon.

[wurlycorner]

My suspicion would be abnormally large suspension travel at the time, or something snagging the handbrake cable caused the handbrake to apply on that one side.
Check the handbrake adjustment on that side is correct.
Beyond that, or something physically jamming inside the drum (large chunk of rust or dislodged friction material as already suggested) there isn't really anything else it could be.

[Pug_XUD_KeenAmateur]

Thanks Wurly, will do.

Seems you've got exceptional taste in Citroens. Possibly one day I'll 'dare' to run a Xantia D Estate, but hopefully the current old girl's got at least a couple of years in her yet.

[wurlycorner]

Or that I'm a complete basket case...


Just a further note that it's not far fetched that large suspension travel can cause hand brakes to come on - I had a friend that ran a knackered Cavalier where the rear brakes would come on frequently while he was driving on the motorway, whenever they hit a bump
As well as checking the adjustment, check to make sure that all the various handbrake cable clamps are correctly in place and nothing is snagged/kinked/taught etc.

[Oldpug]

If that rear wheel locked solid suddenly I would say its the brake lining (or part of it?) come away from the shoe,gone round and locked the drum. I`ve had this happen many times with 205`s,106`s,trouble is when it happens it stays locked and we had a big problem getting the drum off.
If it locked and then freed itself may be the shoe retaining springs or fittings have broken? Two other problems I`ve had with 405 estate rear brakes, the right and left h/brake cables are very prone to seizing,also the flexi brake pipes tucked up by the rear axle can collapse inside,the fluid will not return causing a buildup of pressure to the drum.

[Pug_XUD_KeenAmateur]

Thanks 'OldPug', lovely old 404 there, the white suits it lovely doesn't it.

Funny how different colours suit different cars. I was glad to find myself a white 405 estate, but the red colour of my previous 405 est suited it better.

I had a repeat of the symptom this morning, reversing carelessly around a corner i hit a kerb and in the course of mounting said kerb I felt the brakes apply on that wheel as the suspension (trailing arm on these) travelled. I've now loosened off the handbrake cable and am pretty confident that'll be the end of it.

Also, on a separate note, a cautionary mention..... be careful when buying parts to establish whether they come in 'pairs' or not as the supplier may, as ridiculous as it is, supply you a rather useless 'half of a pair'.

GSF are most definitely not my favourite factors having supplied me via Ebay half of a pair of Anti-Roll Bar Bushes which I didn't realised come as pairs until I'd taken the old one off [so I have an element of fault here for not noticing, to be completely fair, but they're definitely getting a very snotty letter]

.... and they're no longer stock items from my local outlet so I couldn't just pop down the road and rectify my error.

Thankfully a separate Ebayer supplied me two pairs both at an incredibly cheap price and having ordered them at 2pm Thursday they landed on my doormat the next morning, so a 'big up' to 'jolly_good_car_spares_ltd" whom have lived up to their name.

Ebay item numbers 281505458185 and 301576062200 apply

Thanks Everyone !! Invaluable advice once again

[Pug_XUD_KeenAmateur]

Trying out the advice earlier in this thread relating to attaching photo's to a Thread. I thought the Drum Brake pic was a bit boring so there's a less boring one taken at TechnoClassica this year, if it works

http://s77.photobucket.com/user/julian9 ... b.jpg.html" onclick="window.open(this.href);return false;

http://s77.photobucket.com/user/julian9 ... o.jpg.html" onclick="window.open(this.href);return false;

[wurlycorner]

Wrong link copied

[Hell Razor5543]

Like the Maserati. Not sure about the brake though.

[Pug_XUD_KeenAmateur]

Like the Maserati. Not sure about the brake though.

Oooh you calling my brake unexciting?

[Hell Razor5543]

No, just that I cannot offer any assistance (other than to suggest you get the Maserati instead!).