After Brake Shoes Replacement

[aruntantan]

Hi Guys,

Recently I have replaced all my brake shoes, rear and front. Now the when I pushing the brake there is some free movement in the brake pad.

So in order to apply brakes I need to push deeper. Then the garage person check for any air in oil, and did something like "brake katuwak pannawa", not sure what that is.

But result is still the same, and the garage guy said that, since you've replaced all the pads, it'll take sometime to sync and later the you dot need to push this much deeper.

Is this the normal case?.. Or is there something wrong with my brake unit?

Thanks.

[Rumesh88]

Not quite sure what you mean by "free movement in the brake pad". In fact every brake pedal has an initial travel of around 10mm known as the pedal preplay. During this movement the brake pads are not activated and it is quite normal. However, if you experience a reduction in brake force for the same travel of the pedal compared to that before the replacement of pads it could be due to grooves on the brake disc/drum surface. Did you re-surface the brake discs during pad replacement? Get the brake surface checkd for grooves. If the issue is due to grooves eventually the pads will bed-in to grooves as you go on using the car and the brake force may return to normal but it is not the right thing to do. If the discs are grooved then you need to get them resurfaced (skimmed).

[aruntantan]

Not quite sure what you mean by "free movement in the brake pad". In fact every brake pedal has an initial travel of around 10mm known as the pedal preplay. During this movement the brake pads are not activated and it is quite normal. However, if you experience a reduction in brake force for the same travel of the pedal compared to that before the replacement of pads it could be due to grooves on the brake disc/drum surface. Did you re-surface the brake discs during pad replacement? Get the brake surface checkd for grooves. If the issue is due to grooves eventually the pads will bed-in to grooves as you go on using the car and the brake force may return to normal but it is not the right thing to do. If the discs are grooved then you need to get them resurfaced (skimmed).

I meant the travel distance for brakes to engage is like 0.5 to 1 inch. And when after a rapid brake the padel almost getting closer to the bottom edge..

Previously the travel distance is around 10mm as you've mentioned. I want to get it engaged by that traveling distance.

[NRX]

I meant the travel distance for brakes to engage is like 0.5 to 1 inch. And when after a rapid brake the padel almost getting closer to the bottom edge..

Previously the travel distance is around 10mm as you've mentioned. I want to get it engaged by that traveling distance.

Do you get that spongy feeling when you step on the brake pedal ?

[Watchman]

It's probably way too early to tell (because of Rumesh and Arun mentioned)

Drive a few hundred Kilometers and see if it has come back to normal. Unless something was seriously messed up during the brake-pad replacement, it's a fairly simple and straight forward procedure.

[aruntantan]

It's probably way too early to tell (because of Rumesh and Arun mentioned)

Drive a few hundred Kilometers and see if it has come back to normal. Unless something was seriously messed up during the brake-pad replacement, it's a fairly simple and straight forward procedure.

Still the free movement of the pedal continues, after driven around 500km ..

When braking 40/50kmh feel like Im not in full control of the vehicle..

Any good place "brake expert" which I can get help?.. Any recommended places around Colombo?..

[Watchman]

Do you know if your mechanic loosened any valves to let out any brake oil to make space for the thicker new pads? It's possible that this let some air into the system. I made this mistake the first time I tried to change pads myself. You'll need to bleed the system.

IMO, you shouldn't need a expert to resolve this. Just goto a competent mechanic that you trust.

Good luck!

[Kavvz]

Do you know if your mechanic loosened any valves to let out any brake oil to make space for the thicker new pads? It's possible that this let some air into the system. I made this mistake the first time I tried to change pads myself. You'll need to bleed the system.

IMO, you shouldn't need a expert to resolve this. Just goto a competent mechanic that you trust.

Good luck!

You changed your own brake pads? Impressive. Always wanted to give it a shot myself, but haven't had enough confidence in my ability to actually go through with it. Not bad watchman. Not bad at all.

[Watchman]

You changed your own brake pads? Impressive. Always wanted to give it a shot myself, but haven't had enough confidence in my ability to actually go through with it. Not bad watchman. Not bad at all.

It's fairly straightforward.. Just popping out clips/screws to undo the caliper from the mount and the pads from the caliper.. rookie mistake was to think that letting out Brake oil would be the easier way to widen the gap between pads. What you should do is pry them open with a screw-driver.

[Sampath Gunasekera]

It's fairly straightforward.. Just popping out clips/screws to undo the caliper from the mount and the pads from the caliper.. rookie mistake was to think that letting out Brake oil would be the easier way to widen the gap between pads. What you should do is pry them open with a screw-driver.

I have seen suck Brake oil to widen the gap between pads.

https://www.facebook.com/media/set/?set=oa.406513426061092&type=1

[Rumesh88]

I have seen suck Brake oil to widen the gap between pads.

https://www.facebook.com/media/set/?set=oa.406513426061092&type=1

Well, it is almost impossible to push the pistons back with your bare hands. Use a G-clamp.

[Nilantha]

remove air in the break system.

[aruntantan]

Do you know if your mechanic loosened any valves to let out any brake oil to make space for the thicker new pads? It's possible that this let some air into the system. I made this mistake the first time I tried to change pads myself. You'll need to bleed the system.

What do you mean by, you need to bleed the system?.. Need to refill brake oil to remove the air?..

[terrabytetango]

What do you mean by, you need to bleed the system?.. Need to refill brake oil to remove the air?..

More or less. Firstly removing the air via a bleed screw on each wheel and then topping up with brake fluid.

[Davy]

So in order to apply brakes I need to push deeper. Then the garage person check for any air in oil, and did something like "brake katuwak pannawa", not sure what that is.

Your mechanic is referring to the the manual adjusting spur wheel on the rear brakes. This is a small adjuster wheel that can be rotated to bring the liners closer to/further away from the drums. You can see this spur wheel on the lower middle of the following first image (the shiny silver thing).

Some setups are different to that of the first image. You can see that the adjustment spur in the following brakes is right under the slave cylinder. This is the most common setup in my experience.

Anyway, this is what is referred to as "Katuwak pannanawa" by our local mechanics. Your mechanic might have adjusted this screw that caused the brake pads to move further away from the drum. This might be the reason as to why your brakes are not as efficient as they used to be. If this is the case, it just needs re-adjustment. My opinion is that this adjustment spur shouldn't even need adjustment if it was just an ordinary brake pad replacement. Messing up this adjustment can cause unforeseen issues like what OP is experiencing.

Note that this is just one possibility only. Brought this up because I felt like your mechanic has messed up the adjustment.

[The Stig]

Given that the drums are in the rear and the larger brake force is habdled by the front disks do you guys think that an adjustment in the drum could effect the entire pedal travel?

Also curious, op says he has replaced front brake shoes?

[Davy]

Given that the drums are in the rear and the larger brake force is habdled by the front disks do you guys think that an adjustment in the drum could effect the entire pedal travel?

Also curious, op says he has replaced front brake shoes?

Good question, and the answer is yes it can. If the car in question has ABS, then the ABS module will make sure that the brake force is distributed to the 4 corners of the car. The rear being poorly adjusted means more room for the pistons to push the brake liners towards the drum. Even if this was a car without ABS, poorly adjusted rear brakes can affect pedal traversal because the master cylinder will have to pump more fluid through the system for the rear liners to push against the drum.

As for the term OP has used, I assume he was referring to brake pads at the front and liners (shoes) at the rear. His first sentence says that he has replaced them on both front and rear.

One other thing I didn't mention in my previous post is that the adjusters at the back are usually self-adjusting. Only older cars required manual adjustment. The mechanism works in two ways (based on the design):

1. When the parking brake is pulled firmly:

The adjusting mechanism automatically adjusts itself to bring the brake liners to the desired position every time the parking brake is pulled firmly.

2. When brakes are applied firmly when the car is being reversed:

Putting the car into reverse and stomping on the brake pedal hard will cause the self-adjusting mechanism to activate and adjust the liners.

I'm sure OP has pulled the handbrake more than once after the repair, so maybe you can try the second option. Remember that you have to depress the brake pedal hard when in reverse. Take care when doing this. If this does not solve the issue, you can bleed the system to ensure that no air has been trapped in the system.

Edited January 1, 2016 by Davy

[aruntantan]

Good question, and the answer is yes it can. If the car in question has ABS, then the ABS module will make sure that the brake force is distributed to the 4 corners of the car. The rear being poorly adjusted means more room for the pistons to push the brake liners towards the drum. Even if this was a car without ABS, poorly adjusted rear brakes can affect pedal traversal because the master cylinder will have to pump more fluid through the system for the rear liners to push against the drum.

As for the term OP has used, I assume he was referring to brake pads at the front and liners (shoes) at the rear. His first sentence says that he has replaced them on both front and rear.

One other thing I didn't mention in my previous post is that the adjusters at the back are usually self-adjusting. Only older cars required manual adjustment. The mechanism works in two ways (based on the design):

1. When the parking brake is pulled firmly:

The adjusting mechanism automatically adjusts itself to bring the brake liners to the desired position every time the parking brake is pulled firmly.

2. When brakes are applied firmly when the car is being reversed:

Putting the car into reverse and stomping on the brake pedal hard will cause the self-adjusting mechanism to activate and adjust the liners.

I'm sure OP has pulled the handbrake more than once after the repair, so maybe you can try the second option. Remember that you have to depress the brake pedal hard when in reverse. Take care when doing this. If this does not solve the issue, you can bleed the system to ensure that no air has been trapped in the system.

Yes I meant front pads and rear shoes. and my model has ABS.

I am not a regular user of parking brake, when I stopped the vehicle I put into "P", that's it..

Will try the parking brake and the reverse thing and put the results here.

[Davy]

I am not a regular user of parking brake, when I stopped the vehicle I put into "P", that's it..

Simply leaving the car on P without the parking brake engaged leaves a lot of stress on the transmission. Especially if the vehicle is parked on a slope. Always pull your parking brake if you are turning the engine off.

[aruntantan]

Simply leaving the car on P without the parking brake engaged leaves a lot of stress on the transmission. Especially if the vehicle is parked on a slope. Always pull your parking brake if you are turning the engine off.

Oh is that the case. If its a high slope I use parking brake. not otherwise. :speechless-smiley-004:

Anyway thanks for the tip..