Brake fluid change at dealership

[pebo48]

Hi booked my car in for a brake fluid change at my local dealer and asked the question. "Do you bleed the clutch as well seeing as they share the same fluid" they said "No we dont bleed the clutch as part of a fluid change". I found that strange would the old fluid in the clutch not contaminate the new fluid they have just replaced or have I got it all wrong just seems odd not to remove ALL old brake fluid 🤔 

[aubrey]

So they have a pressure bleeder all hooked up and they can't be bothered to access the clutch bleed nipple.

Exactly why I always do this myself.

Maybe this is a time thing due to access, I've often had to remove items to get to the clutch bleed nipple. Some are fragile plastic and if they broke that on a concentric slave cylinder it's big remedial work. Coupled with clutches don't work under the heat load of brakes so I bet it's not so necessary.

I always do the clutch too myself as an extra half hour or hour is not a personal issue, for a garage that would be different.

Interesting question and I'm interested in other answers.

[J.R.]

4 hours ago, pebo48 said:

I found that strange would the old fluid in the clutch not contaminate the new fluid they have just replaced or have I got it all wrong just seems odd not to remove ALL old brake fluid 🤔 

 

No it will not, it does not recirculate and is drawn from a seperate tapping on the reservoir higher up than the brake one so a clutch fluid leak will not affect the braking system but will bring up a warning light.

 

Clutch operation will not be diminished by moisture content in the fluid.

 

2 year brake fluid changes are simply an easy money spinner, my MK1 Octavia was tested every year during the Telethon at our Lycée Professionale using an instrument calibrated every year and the fluid was always perfect right up to the day it went to the scrapyard at 17 years old and 325000 miles.

[rum4mo]

I always change the brake fluid on our family’s cars, but tend to use the “plastic slave/secondary cylinder” as a good enough reason not to bother with the clutch leg fluid.

Obviously there will be a slight equalising of moisture content between the.fresh fluid and the old fluid in the clutch fluid leg - so the clutch leg fluid will very slightly hand over some of its moisture, which is good enough for me.

One day/year,I will draw some out of the clutch legs and see what it looks like - maybe.

[pebo48]

Thanks for all the replys guys...had a look today and slave is plastic so might leave well enough alone 😁😁

[Doily]

I've never changed any hydraulic fluid on any of the cars I've owned, some with 150k+ on the clock and 20 years old. Never had any issues apart from normal wear and tear on pads and shoes, etc.

Have I been lucky?

[J.R.]

No, and you havn't been a pigeon either!

 

NB Un pigeon in French means a willing victim.

 

A car braking system will work very well filled with nothing but water, in fact it will have a harder pedal, not advisable as all the components will corrode and the fluid would boil under sustained heavy braking but 99% of vehicles never experience those conditions so an unmeasurable amount of water absorbed is pretty much a theoretical and hypothetical risk used to upsell by main dealers.

 

And I know this for sure having unwittingly experienced it with a very measurable amount of water in the brake system of one of the first RHD Ford Galaxy people carriers before Ford was forced to admit the problem and do a recall, water ran from the screen into a well on the not properly sealed master cylinder cap and then into the brake fluid, it then made its way down by gravity to the front disc calipers and concentric clutch slave cylinder displacing the hydraulic fluid out of the reservoir.

 

I drove that thing loaded with all my business tools and materials  like the roads were my personal race track, coming down Detling hill towing a trailer with my race car the fluid boiled and I lost the brakes, as a race driver I knew exactly what had happened but as I had just changed the pads I blamed the new Mintex ones thinking they had faded and generated too much heat.

 

I immediately swapped the pads and bled the system, nothing but pure rusty water came out of the front calipers, I flushed and refilled the whole system and tried to conclude how the water could have got in, Ford at this stage were in full on denial mode, I had bought the car as a write off with the loom and dashboard burnt out following an electrical fire (another Ford denial jobbie!) and wrongly concluded that the fire brigade had used their high pressure hose under the bonnet and the water stream had got into the fluid reservoir.

 

Later on the master cylinder failed through corrosion and later still the concentric clutch slave cylinder.

Edited 22 March by J.R.

[Jocko]

I too, over 60 years of car ownership, have never changed the brake or clutch fluid on any car I have owned. The longest I have owned a vehicle is 170,000 miles and 13 years. I have never had brake issues other than the usual pad wear.

[classic]

On 20/03/2024 at 06:16, pebo48 said:

Hi booked my car in for a brake fluid change at my local dealer and asked the question. "Do you bleed the clutch as well seeing as they share the same fluid" they said "No we dont bleed the clutch as part of a fluid change". I found that strange would the old fluid in the clutch not contaminate the new fluid they have just replaced or have I got it all wrong just seems odd not to remove ALL old brake fluid 🤔 

You are absolutely correct. In fact the official Skoda workshop manual brake fluid change procedure includes the clutch slave cylinder but I very much doubt many dealers (or any garage !) actually do it. Whether or not it even needs doing at all, I don’t know, but most manufacturers seem to specify it as maintenance.

Edited 22 March by classic

[sepulchrave]

22 hours ago, Jocko said:

I too, over 60 years of car ownership, have never changed the brake or clutch fluid on any car I have owned. The longest I have owned a vehicle is 170,000 miles and 13 years. I have never had brake issues other than the usual pad wear.

 

If you drive like Miss Daisy then you won't have any trouble, but if you ever descend a very steep hill or drive the car hard then you will experience brake fade due to steam bubbles forming in the calipers as the fluid temperature exceeds 100 °C

 

Brake fluid needs changing occasionally.

[J.R.]

On a track yes, very quickly in fact, on the road, for 99% of people 99% of the time, never in a million years, when it happened to me I was driving like a loony dowhill through bends towing my racecar and 2 sets of wheels and tyres on a heavy homebuilt trailer the Galaxy loaded with all my tools, paddock gear and camping gear and unbeknown to me the front brake calipers full of rusty water.

 

My MK1 Octavia was checked every year with a calibrated garage tester, there was no detectable fluid content right up to the day it was scrapped after 17 years and 32500 miles, there was no H2O to boil, water being absorbed through the brake hoses is an old wives tale, master cylinder caps are very well sealed with gallery vents (the MK1 Galaxy aside) there really is no way for fluid to become moisture laden these days.

 

I also drove that Octavia for 18 hot laps of Croix en Ternois circuit with 3 passengers under instruction, its the hardest circuit that I know on brakes and they were only good for the first 2 laps, no late braking thereafter and you never apply the handbrake in the paddock after that, it was heat fade and some fluid fluid boiling but not because of water content, that feels very different and is unmistakable. It was 5 years old then with I reckon 225000 miles on the clock.

Edited 23 March by J.R.

[Jocko]

16 hours ago, sepulchrave said:

 

If you drive like Miss Daisy then you won't have any trouble

I have driven hard and fast for most of my motoring life. I was an out-and-out lunatic for most of my early driving career. I have driven single-seaters and rally cars, trucks and buses. It is only since retiring that I toned down my driving, as a nod to my age and to reduce wear and tear on my cars.