[Mortis]

Guys since last week Ive been having problems with the brakes on my Beat. My FNG has done a temporary fix but I need to get it fully rectified ASAP as I have a Mumbai-Udaipur return trip coming up in two weeks so obviously properly functioning brakes are essential ! Details of the problem are below.

I've not been using my car much at all over the past month or so as one section of the road in the direction I mostly travel is closed for repairs (Juhu SNDT) and taking the car via the detour take over 45mins easily most of the time for a 500m stretch so I walk past it instead.

I've been facing a string of coincidental small car problems over the past couple of months since I planned the road trip.

One of these was a completely dead battery followed by the alternator conking out. Both of these were rectified.

I mention this because at the time of alternator failure, along with the battery warning light the parking brake light was also glowing. I was asked by a few people to check brake fluid levels which were fine and some research lead me to believe that if alternator has failed completely then only battery icon will glow but if alternator is producing low voltage below 12v then the brake warning light also glows. It did turn off after repairing the alternator.

Now last week I took the car out for errands in the opposite direction and since the car was idle for some time and it had been raining, obviously there was some rusting and scraping noises around the rear drums. While out I finally came across a slightly empty stretch and thought I would try and fix the scraping noise caused by the rust by doing a bit of hard braking. Nothing crazy or unsafe, just 40km/hr to 0 and that too near speedbreakers of which there were several on this stretch.

So first time around I stepped on the pedal after which the sound reduced. 2nd time around I used only the hand brake to concentrate braking on the rear and sound reduced further.

I thought to myself that once more should do it but using only the handbrake didn't feel right so I'll use the pedal only. This time I pressed the pedal and it sank in completely with barely anything happening !! To quote Jeremy Clarkson many poos came out !! Managed to control the car using engine braking and the handbrake. Thereafter drove straight to my FNG in 2nd slowly using only engine braking and the handbrake which was also kind of weak. Pedal was pretty much useless.

The FNG found one rear cylinder had overheated and stuck. Brake oil too was hot. He allowed things too cool and did a bit of servicing and bleeding, etc.

The pedal now has a lot of travel and is very light with only slight braking in the initial "normal" zone and works normally only in the last inch or two of travel. This is extremely unsettling and not normally as gradual braking is not really so easy now. It kind of has a clutch like feel to it.

My FNG says that the overheated brake fluid has most likely damaged the master cylinder seals and the master cylinder has to be replaced.
Is this the most likely solution ?

I have tried checking for vaccuum issues but that seems fine. Brakes were pumped a couple of times with engine off, they hardened and when half pressed and engine was started it became softer/sank again.

To check the master cylinder seals it is recommended to press the brake slightly and if seals are bad the pedal will sink to the floor. Will the pedal sink on its own in this case ? Or do they mean it will be soft and with continued application of light pressure it will go down normal but with less resistance like a sponge to the last inch or so which is what is happening ?

Another option could be ballooning of brake lines at some point due to the overheating. My mechanic did not notice any but could it produce similar symptoms ?

Really appreciate some help and advice so that I can rectify it.

[aravind.anand]

Several years ago my aunt had an accident where her car ended up sideways and she was rescued out of the car by passersby who had to break the windshield to pull her out. She had her seat belt on, and that was certainly what had saved her. She spent few days at the hospital and she gave up driving after that nasty incident. She had been driving for close to 15 years before this incident happened - starting from a Maruti 800, she went through myriad of cars including Hyundai Santro, Ford Ikon, Skoda Octavia and Honda Civic.

When everything settled down, after she had been discharged from the hospital and she seemed less rattled and stressed we asked her what happened... To which she said the brake pedal went all the way down but the car never responded and to avoid the traffic she had to swerve and went off the road and the car went sideways, slid for 50 meters and hit a tree. I had not posted about this anywhere till now as it was rather personal. But this thread literally shook me up!

My aunt was driving a Chevrolet Beat TCDi too

[saket77]

I remember when you posted the issue previously and I replied there too. However coming to the problem, I hope the rear brake cylinders were replaced and not repaired. Check brake fluid level.
Next, your rear brake shoes are either worn out or need adjustment. Currently there is probably too much clearance between the shoe and the drum. Disc brakes at the front are self adjusting but the rear drums aren’t. So, service the rear brakes as well. Last, get brake bleeding done to drive out any air that may have gotten into the system.

This is all; assuming that there are no leaks in the system. To check for leak, start the engine, apply and hold the brakes on a stationary car. The pedal should not sink. If it does, then you have a leak somewhere.

Trust this helps.

Regards,
Saket

[Mortis]

Originally Posted by aravind.anand

My aunt was driving a Chevrolet Beat TCDi too

Quite shocking Arvind. Glad she made a recovery though it's unfortunate it shook her enough to give up driving

Originally Posted by saket77

I remember when you posted the issue previously and I replied there too.

Regards,
Saket

Hi Saket, thanks for the advice. The rear brake pads were replaced just about 3-4000km ago. The mechanics first thought was that one of the rear pads might have cracked so he opened it up as soon as I took it in. Both pads were fine. But the whole rear brake system was boiling hot and on the left side the brake cylinder/booster whatever it's called that looks kind of like a D cell battery had locked up due to heat expansion. He left it to cool for some time and then it became free again. After this he did various small adjustments including bleeding the lines to get it back to usable condition, no idea of what all exactly. Now the feel of the brake pedal is like a soft clutch. It does engage now unlike just after the incident but say if the clutch has 4 inches of travel, now in the first 3 inches it's very soft and spongy with maybe 5-10% braking effect and then the remaining braking level range happens in the last inch. When functioning normally I would start feeling resistance and braking effect right after 1/2 or 1 inch of pedal travel and increasing till the pedal was pushed in all the way. There is not much resistance now.

I didn't exactly get the last part about the pedal sinking and leak checking. Do you mean that the pedal will have extremely less resistance and with light pressure and movement of my foot it will go in (like normal operation but "easier") or that if I give it a tap with my foot the pedal will continue moving in, separating away from my foot if I leave my foot in the same place. Sorry if this sounds like a stupidly phrased question because I had the same doubt with the testing method suggested online for the master cylinder and it feels weird to translate motions and feelings of this nature into text.

Wrt to the info I have given above is there any more advice on the problem, solution or testing ?

[saket77]

I strongly feel that the brake line needs bleeding. Check fluid level as well.

Regarding the circuit leak check, what I meant is that first start the engine. Now, without moving the car, apply and keep holding the brake pedal. Keep applying foot pressure on the pedal. The pedal should not sink to the floor. Hope it’s clear now.

Regards.

[SS-Traveller]

Originally Posted by Mortis

Guys since last week Ive been having problems with the brakes on my Beat. My FNG has done a temporary fix...

Please have the brake system overhauled before going on your trip.

How old is the car, and how many km has it done?

Change the rear wheel cylinders and brake drum & brake shoes (I believe the Beat has brake drums at the rear, not discs).

Open and check the front disc and all components associated with it. Replace pads if required. Check calipers and pistons for stickiness - if required, change.

Flush the master cylinder and lines with new brake oil.

If the master cylinder and/or brake booster are faulty according to your FNG, replace them. Not a good idea to try to repair these.

Refill with fresh oil of correct grade as recommended, bleed the lines, and you should be good to go.

[Mortis]

Originally Posted by saket77

snip
Regards.

Will get the bleeding done. Fluid levels are fine and have been topped off after the bleeding.
Sorry I'm still not clear on the sinking to the floor bit !
When functioning normally and I apply pressure to the pedal, it used to sink to the end of its actuation range, but I used to feel resistance/springiness throughout the travel range and the brakes would have increasing levels of "bite" the more I pushed.
Now when I apply pressure for 75% of the travel range there is not much resistance, just a light light sponginess with only slight bit of braking effect say similar to engine braking or lower. Then in the last 25% of travel range close to the floor I start feeling that resistance and brakes start to bite but since it occurs in such a small band it's hard to finely manipulate the level of braking I want if you get what I mean ? It's kind of either "some" or all of it in that little band.

Originally Posted by SS-Traveller

Please have the brake system overhauled before going on your trip.

How old is the car, and how many km has it done?

Change the rear wheel cylinders and brake drum & brake shoes (I believe the Beat has brake drums at the rear, not discs).

Open and check the front disc and all components associated with it. Replace pads if required. Check calipers and pistons for stickiness - if required, change.

Flush the master cylinder and lines with new brake oil.

If the master cylinder and/or brake booster are faulty according to your FNG, replace them. Not a good idea to try to repair these.

Refill with fresh oil of correct grade as recommended, bleed the lines, and you should be good to go.

The car is a bit more than 8 years old and has done 49000km. The rear drum brakes got new pads in November along with new brake oil. Front pads were cleaned and serviced then. Last week also they were inspected and have a good amount of life left maybe 5mm or so. As such everything was working fine until my failed attempt at cleaning corrosion off the drums !

So for now both of you suggest getting new brake fluid and bleeding and checking the functioning of all the brakes with the tyres off as the first step ?
If it looks fine and bleeding with new oil doesn't work then replacement of master cylinder should be the next step right ?
Could my symptoms indicate ballooning of the brake lines due to heat ?

I apologize for being so long winded. I have only two weeks to fix this critical component and not enough time in between to get it done along with the bad weather and road work so I'm trying to zero in on the main problem the best I can. At the same time I want to see if a cheaper component has to be replaced first to fix the problem rather than an expensive one like the master cylinder with my recent bad luck. I've already spent more on repairs this year than I wanted to after I decided to keep the car for a couple more years. All the gremlins decided to pop up in a short span after my decision
But at the same time it would also be stupid to cheap out on brake repairs Vs say an ICE problem !

[SS-Traveller]

Originally Posted by Mortis

Now when I apply pressure for 75% of the travel range there is not much resistance, just a light light sponginess with only slight bit of braking effect say similar to engine braking or lower. Then in the last 25% of travel range close to the floor I start feeling that resistance and brakes start to bite but since it occurs in such a small band it's hard to finely manipulate the level of braking I want...
...
The car is a bit more than 8 years old and has done 49000km. The rear drum brakes got new pads in November along with new brake oil. Front pads were cleaned and serviced then.

Replace all the flexible hoses on the brake lines, change the rear wheel cylinders, check if the front pistons need replacement (presence of rust will decide that), and then flush and replace the brake oil.

Has your car been standing in wheel-deep water recently?

[Jeroen]

All the problems started due to the overheating. I am not sure what caused that and no matter what, that needs to be properly fixed. Overheating due to some rust is rare, to your point, the rust usually disappears quickly after a few braking actions. So something else must have got stuck. On drum brakes, overheating is nearly always a mechanical problem with the brake shoes simply not moving back when the brake pedal is released. That could be due a problem with the brake cilinder, to much dirt etc. No matter what, have this checked and ensure this brake works properly again.

You definitely had vapour lock in that brake and that means the braking fluid was boiling! That can easily damage seals.

If the braking fluid was replaced (it really ought to, after boiling) and the system was properly flushed and bled it should be back to normal.

What is left appears to be the pedal sinking down much further than before. That could indicate a damaged master cilinder. I assume your car has, as do almost all cars, some sort of dual redundancy. Which means your four brakes are pressured through two independent hydraulic lines/circuits from the master cilinder. If one internal seal of the master cilinder gets damaged, the other one will still operate two out of the four brakes. But the pedal stroke tends to be longer/deeper. Also the braking action will be less. Obviously, as you only use 2 brakes instead of the 4.

It can be easily checked by visual inspection and or trying to rotate all four wheels whilst pressing on the brake.

No matter what, do get it sorted properly before going out on the road again!
Good luck.

Jeroen

[Mortis]

Thanks a lot for the advice guys. Will start working on it from tomorrow.
Will start with new brake fluid and bleeding.
Followed by visual inspection of the brakes functioning and brake lines and boosters
Then checking to see if only one half of the brakes work.
Finally replacement of master cylinder

The car has not been standing in deep water more than an inch

[Jeroen]

To add, just an easy check on the booster;

Before starting the engine, push the brake pedal 4-5 times. Then push the pedal lightly till you feel some pressure. Start the engine, your brake pedal should move a bit deeper. If it doesn’t there is something wrong with the brake booster system.

Jeroen

[Mortis]

Originally Posted by Jeroen

To add, just an easy check on the booster;

Before starting the engine, push the brake pedal 4-5 times. Then push the pedal lightly till you feel some pressure. Start the engine, your brake pedal should move a bit deeper. If it doesn’t there is something wrong with the brake booster system.

Jeroen

Already done that and it works fine. Mentioned it somewhere in the clutter of my first post under the name vaccuum check.
So does this indicate the boosters are fine ?

[Jeroen]

Originally Posted by Mortis

Already done that and it works fine. Mentioned it somewhere in the clutter of my first post under the name vaccuum check.
So does this indicate the boosters are fine ?

My bad, missed that. Looks like the brake booster is fine.

Good luck
Jeroen

[Mortis]

Originally Posted by Jeroen

My bad, missed that. Looks like the brake booster is fine.

Good luck
Jeroen

So does this change your diagnosis in anyway or point more strongly towards the master cylinder ?

[Jeroen]

Originally Posted by Mortis

So does this change your diagnosis in anyway or point more strongly towards the master cylinder ?

Again, make sure that the brake that overheated is working 100%. If there is anything wrong, worn or badly adjusted for instance, it might cause problems. Poorly adjusted brake drums (too much play) will also lower your brake pedal!

If that brake is working properly and properly adjusted, new brake fluid and properly bled, only then I would do that check on the master cilinder as I suggested. So make sure the brake shoes have sufficient thickness and are properly adjusted, or get them replaced.

Your problem started with this one brake, so before doing anything make sure it is in 100% working order.

Good luck
Jeroen