Braking Question

[Pattaya Spotter]

Recently it's been that I've noticed my brakes don't seem to engage, or do so only lightly, when I first start up my car. I have to pump the brake pedal a couple times before I get any real braking action. It seems like I have to "prime" the system to get it to work. It then works fine until the next time I start up the car. I've had a look a the brake fluid reservoir and it's full. What else could be causing this problem?

[KannikaP]

Air in the hydraulic system. Get it bled.

[4MyEgo]

11 minutes ago, Pattaya Spotter said:

What else could be causing this problem?

As KannikaP said above, hope to it man !!!

[DavisH]

3 minutes ago, KannikaP said:

Air in the hydraulic system. Get it bled.

This....had a 1974 mini...been there done that;)

[KhunLA]

You ask on a forum, instead of taking to dealer or shop to deal with it.

 

Does sound like air in the lines or low level of fluid, and better dealt with at the auto shop, instead of the internet.

 

Mind boggling ... ????

[PJ71]

7 minutes ago, KhunLA said:

You ask on a forum, instead of taking to dealer or shop to deal with it.

 

Does sound like air in the lines or low level of fluid, and better dealt with at the auto shop, instead of the internet.

 

Mind boggling ... ????

Probably get more sense on here than a dealer, some of the members on here have great knowledge.

[KhunLA]

Just now, PJ71 said:

Probably get more sense on here than a dealer, some of the members on here have great knowledge.

Yes, but since he states 'every time I start', implies he's been driving around with it, instead of tending to the issue.  Hope he keeps his hand on the hand brake, if having, while driving.

[Lacessit]

11 minutes ago, KhunLA said:

You ask on a forum, instead of taking to dealer or shop to deal with it.

 

Does sound like air in the lines or low level of fluid, and better dealt with at the auto shop, instead of the internet.

 

Mind boggling ... ????

What's mind-boggling is posters who don't read the OP, where it is stated quite clearly the brake reservoir is full.

[brianthainess]

It sounds more like a problem with the vacum servo,  are your brakes disc all round or drums on the rear ? if drums&shoes, they have automatic adjusters that work in conjuction with the handbrake, they can sieze up, especially if the driver dosn't bother to use the handbrake when parking. Get them checked.

[bunnydrops]

master cylinder seal?

[HauptmannUK]

You can do some diagnosis of the problem yourself. I frequently get asked to check braking systems......here are some basic tests:

1. With the car parked, engine off, handbrake off, gear in 'P'....Press gently on the brake pedal several times to relieve any vacuum in the servo.  Now press down firmly on the pedal. It should come to an abrupt 'hard' stop clear of the carpet/floorpan.  Any springiness/sponginess at the bottom of its travel indicates air in the system and bleeding is required. Ditto if the pedal contacts the carpet.

2. Maintain some pressure on the pedal. If it slowly sinks further under your foot then you likely have a problem with master cylinder seals.

3. Now, release the pedal and then press down again, keeping moderate pressure on the pedal, start the engine. Over a few seconds you should feel the pedal 'sink' under your foot. This is the vacuum servo providing assistance.  If nothing happens then you have a faulty servo.

 

If the system passes the above tests but you still need to pump the pedal on first use the its possible the rear drum brakes are way out of adjustment. They need stripping, cleaning and adjusting.

 

I would recommend changing brake fluid every three years.  Toyota/Lexus seem particularly prone to sticking caliper slide pins on lightly used cars. Its worth greasing the slide pins every couple of years.

[degrub]

Or the vacuum supply to the vacuum booster servo. Almost sounds like a vacuum leak is sealing off once the engine warms up. Lots of options there. 
 

if he hasn’t been bleeding out the brake fluid at least every few years, likely water absorbed into the break fluid giving that spongy “air” feeling.

 

Needs to get it to a shop with a good mechanic if a simple bleed doesn’t correct it, i think.

[Kwasaki]

"Start car and have to pump brake pedal to get any brakes",  you can believe me if you wish but that means take the car to a workshop and get the brakes fixed asap. 

[HauptmannUK]

5 minutes ago, Kwasaki said:

"Start car and have to pump brake pedal to get any brakes",  you can believe me if you wish but that means take the car to a workshop and get the brakes fixed asap. 

Yes I agree. Any brake problem should be attended to urgently.

[Pattaya Spotter]

10 hours ago, KhunLA said:

You ask on a forum, instead of taking to dealer or shop to deal with it.

 

Does sound like air in the lines or low level of fluid, and better dealt with at the auto shop, instead of the internet.

 

Mind boggling ... ????

I'm not too mechanically inclined and have received good care care advice here before...really just wanted to know if it was a minor or major problem so when I do take it in for a fix I'm not sold some expensive unnecessary procedure.

 

My driveway is on an incline and the first time I noticed it I actually did have to slam on the parking brake or I would have rolled out into the street ????

[Pattaya Spotter]

10 hours ago, brianthainess said:

It sounds more like a problem with the vacum servo,  are your brakes disc all round or drums on the rear ? if drums&shoes, they have automatic adjusters that work in conjuction with the handbrake, they can sieze up, especially if the driver dosn't bother to use the handbrake when parking. Get them checked.

Rear drums I believe...and I generally don't use the parking brake when parking. Recently I did move to a new place on an inclined street and have started to use it and this issue arose within a couple weeks????

[Pattaya Spotter]

9 hours ago, HauptmannUK said:

You can do some diagnosis of the problem yourself. I frequently get asked to check braking systems......here are some basic tests:

1. With the car parked, engine off, handbrake off, gear in 'P'....Press gently on the brake pedal several times to relieve any vacuum in the servo.  Now press down firmly on the pedal. It should come to an abrupt 'hard' stop clear of the carpet/floorpan.  Any springiness/sponginess at the bottom of its travel indicates air in the system and bleeding is required. Ditto if the pedal contacts the carpet.

2. Maintain some pressure on the pedal. If it slowly sinks further under your foot then you likely have a problem with master cylinder seals.

3. Now, release the pedal and then press down again, keeping moderate pressure on the pedal, start the engine. Over a few seconds you should feel the pedal 'sink' under your foot. This is the vacuum servo providing assistance.  If nothing happens then you have a faulty servo.

 

If the system passes the above tests but you still need to pump the pedal on first use the its possible the rear drum brakes are way out of adjustment. They need stripping, cleaning and adjusting.

 

I would recommend changing brake fluid every three years.  Toyota/Lexus seem particularly prone to sticking caliper slide pins on lightly used cars. Its worth greasing the slide pins every couple of years.

Thank you for the detailed reply. I will definitely use the suggestions to test the system. 

 

Thanks for all the replies...seems to be a few possibilities. It's time for an oil change so I will take it to the dealer and add the brake check to the check list.

[In the jungle]

Only one point I would add to the excellent advice you received earlier.

 

If you are having work done on the brake system try and get them to use DOT4 brake fluid.  DOT3 is commonly used in Thailand but it is a lower spec than DOT4 and DOT3 is not sold in my home country in Europe with good reason.

 

DOT4 is reasonably easy to get in Thailand.

 

 

[Liverpool Lou]

On 10/10/2022 at 9:27 AM, PJ71 said:

Probably get more sense on here than a dealer, some of the members on here have great knowledge.

But the members here are not going to be fixing his brakes.   In the meantime, while he's digesting the internet's opinion, he's driving around with faulty, dangerous brakes.  Whatever advice he gets here will be disregarded when he goes to a mechanic so probably best for him to just get them fixed.

[Liverpool Lou]

On 10/10/2022 at 10:29 AM, HauptmannUK said:

You can do some diagnosis of the problem yourself. I frequently get asked to check braking systems......here are some basic tests:

1. With the car parked, engine off, handbrake off, gear in 'P'....Press gently on the brake pedal several times to relieve any vacuum in the servo.  Now press down firmly on the pedal. It should come to an abrupt 'hard' stop clear of the carpet/floorpan.  Any springiness/sponginess at the bottom of its travel indicates air in the system and bleeding is required. Ditto if the pedal contacts the carpet.

2. Maintain some pressure on the pedal. If it slowly sinks further under your foot then you likely have a problem with master cylinder seals.

3. Now, release the pedal and then press down again, keeping moderate pressure on the pedal, start the engine. Over a few seconds you should feel the pedal 'sink' under your foot. This is the vacuum servo providing assistance.  If nothing happens then you have a faulty servo.

 

If the system passes the above tests but you still need to pump the pedal on first use the its possible the rear drum brakes are way out of adjustment. They need stripping, cleaning and adjusting.

 

I would recommend changing brake fluid every three years.  Toyota/Lexus seem particularly prone to sticking caliper slide pins on lightly used cars. Its worth greasing the slide pins every couple of years.

Then, after all that, take it to a dealer/mechanic and ask them to fix what's actually wrong and hope that his brakes don't fail while he's wasting time reading Thaivisa.   

[Liverpool Lou]

On 10/10/2022 at 7:49 PM, Pattaya Spotter said:

I'm not too mechanically inclined and have received good care care advice here before...really just wanted to know if it was a minor or major problem so when I do take it in for a fix I'm not sold some expensive unnecessary procedure.

"...just wanted to know if it was a minor or major problem".

Faulty brakes are a major problem, obviously.

 

So what are you going to do?  You say that you don't know anything mechanical so after you've read about all the different possibilities here you're just going to take it to a mechanic anyway who'll give you an opinion after actually examining the car.  Are you going to dispute what the dealer/shop tells you is actually wrong based on a number of possibilities proffered here?   Can't see the sense in that. 

 

Hope you get it fixed before the brakes pedal just sinks to the floor in the emergency that will require them to work properly.

[CharlieH]

If its noticeable when you start the car it could be the brake servo, master cyclinder seals, air in pipes calliper seals, any number of possibilities.

 

Anything brake related like that should be taken quickly to a garage for test and inspection.

 

Your life could literally depend on it. DONT WAIT.

[brianthainess]

On 10/10/2022 at 7:53 PM, Pattaya Spotter said:

Rear drums I believe...and I generally don't use the parking brake when parking. Recently I did move to a new place on an inclined street and have started to use it and this issue arose within a couple weeks????

It is very bad driving pratice not to use the PARKING brake, if automatic you could end up with a broken park pin inside the gear box. get the rear brake drums removed and have them checked to see if the self adjusters are not sized. Even at red lights select nueutral apply hand brake, sitting with your foot on the brake, or clutch is bad driving, if someone hits you from behind off comes your foot and BANG ! into the vehicle in front, could be a kid on a M/C !!!!! Learn to drive !!

[HauptmannUK]

8 hours ago, Liverpool Lou said:

But the members here are not going to be fixing his brakes.   In the meantime, while he's digesting the internet's opinion, he's driving around with faulty, dangerous brakes.  Whatever advice he gets here will be disregarded when he goes to a mechanic so probably best for him to just get them fixed.

Asinine comment.

The OP came looking for advice and was advised (several times) to get the car fixed as a matter of urgency. Also advised of faults that could lead to the symptoms he's experiencing.  I doubt this thread has caused him to 'drive around with faulty brakes while digesting the Internet's opinion' - more likely he's learnt something and consulting a mechanic quicker than he otherwise might have done.

[DaRoadrunner]

Number one likely cause.... master cylinder seals. Do not try to replace the seals, just buy a new master cylinder. Do it now before you get to the point where the pedal goes all the way to the floor.... no brakes!

 

Other main causes..... air in brake lines or old contaminated brake fluid (it is hydroscopic.... absorbs moisture and causes spongy pedal). Change fluid and bleed system.

[Pattaya Spotter]

 

So here is the official diagnosis and repair cost estimate for my braking problem. 

 

1. The power brake master cylinder needs to be replaced (#1 on diagram). They say this is the source of air in the brake lines. The entire unit needs to be replaced...it cannot be repaired or rebuilt with parts.

 

2. The brake fluid reservoir unit is replaced.

 

Total cost 20,000 baht and 1-2 week wait for the parts. They recommend I leave the car while I decide whether to have the work done (I agree).

 

Does thus sound reasonable ...obviously there is a problem but is replacement of the entire units, as opposed to repair, necessary? Some background ...about a year ago my air-con in the car wasn't working (no cooling) and this dealer dx'ed a new condenser unit was necessary at a cost of about 40k. I took it to a local car air-con shop and they diagnosed the same problem but repaired it for about 10k (and it's been fine since).

 

I guess most dealers would rather just replace entire units than fix broken parts (easier and more profitable). Should I get a second opinion? This is a 9 year old car and the first major brake issue...maybe it's just worn out and replacement is the proper repair?

 

[PFMills]

Have you priced the bits up yourself on the internet

 

Have you had an estimate from another garage

 

PS  A well known poster on this site just suggested to me that maybe you should go and talk to B Quick.  Hopefully the bleed nipples are not rusted up