Motorhome Jargon Brake Fluid (1 Viewer)

[Cookieboy68]

I have a freind who's a mechanic with a workshop.ive been there this week tinkering on the moho .Checking things over, and he got his Brake fluid checker out to see what state the brake fluid was in .The fluid checker checks for water content in the fluid
It has a l.e.d read out that goes like this
GREEN ...EXCELLENT
GREEN AMBER.....GOOD
AMBER....OK
RED AMBER ....TIME TO GET IT DONE
RED......DO IT NOW
For those not in the know water in your fluid not good,under heavy braking the water boils and you lose braking. Mine was amber red,so I'm doing it next week.
I bought the moho 2 years ago ,so I don't know when it was last done.
I hope this info is useful to you fellow funsters

 

[ivorantony]

It’s worthwhile to change the fluid every 5 years regardless of water content and use DOT5.1 fluid that is superior to the usual DOT4 in most vehicles,

 

[LesW]

I have a brake fluid checker, imagine my surprise to see it indicate water in a new unopened tin of fluid.

In all my years as a qualified mechanic in the 60's and 70's, brake fluid was never a serviceable item, what made it so?

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[PP Bear]

Just changed mine, on the Fiat don’t forget the clutch as well, which turns out to be really easy.

Had SWMBO sat in the drivers seat complaining of leg ache as she pumped the pedal when required. It’s what dems women are for..

 

[Silver-Fox]

I have a brake fluid checker, imagine my surprise to see it indicate water in a new unopened tin of fluid.

In all my years as a qualified mechanic in the 60's and 70's, brake fluid was never a serviceable item, what made it so?

Making money from it

 

[ivorantony]

Making money from it

Not quite, the fluid being hydroscopic will absorb water overtime and if left in the system will cause corrosion to master cylinders pistons/ callipers and ABS pumps and modulators, so for the sake of £20 of fluid it can save
a substantial amount in the long run,
and obviously with a lot of water in the system then seriously bad brake fade will be the result,
I make it a habit of replacing my fluid every time I change my pads and consider it a good insurance,

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[Silver-Fox]

Not quite, the fluid being hydroscopic will absorb water overtime and if left in the system will cause corrosion to master cylinders pistons/ callipers and ABS pumps and modulators, so for the sake of £20 of fluid it can save

I thought it was a sealed system and for water to cause rust requires oxygen?


I do know it’s hygroscopic but the point being made it never used to be a service item.

Similar to all the box ticking done at a “service”

 

[Cookieboy68]

Wow ,and here's me thinking I was passing on useful information, I'll keep shtum in future

 

[ivorantony]

I thought it was a sealed system and for water to cause rust requires oxygen?


I do know it’s hygroscopic but the point being made it never used to be a service item.

Similar to all the box ticking done at a “service”

Sixty years in the motor trade and lost count of the number of seized wheel cylinders and corroded calliper pistons I have had to replace, admittedly they were using DOT3 and DOT4 fluids, as I said the later DOT5.1 is much better and doesn’t absorb as much water as the earlier type,
system cannot be sealed as you must allow for air to replace lowering fluid levels as your pads/ shoes wear,,

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[olley]

This is my opinion as to why until disc brakes became common it wasn't necessary to change fluid regularly.

Brakes convert motion into heat, as drum brakes are less effective than disc they have less heat to transfer to brake fluid.
Also the pad in disc brakes presses directly onto the piston making the heat transfer very quick.

 

[tacr2man]

Since DOT 3 and 4 and 5.1 are all glycol-based brake fluids they are compatible with each other, which means they can be readily mixed without harming your brake system. It is important never to mistake DOT 5.1 (glycol-based) with DOT 5 which is silicone-based and should never be mixed with any other DOT fluid. DOT 5 is used mostly in classic cars that remain in storage for long periods and need a brake fluid that does not absorb water. Dot 5 is incompatible with abs systems

 

[EuroTrotters]

Not quite, the fluid being hydroscopic will absorb water overtime and if left in the system will cause corrosion to master cylinders pistons/ callipers and ABS pumps and modulators, so for the sake of £20 of fluid it can save
a substantial amount in the long run,
and obviously with a lot of water in the system then seriously bad brake fade will be the result,
I make it a habit of replacing my fluid every time I change my pads and consider it a good insurance,

I got that wrong for many years, still do. You mean “hygroscopic”

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[Silver-Fox]

system cannot be sealed as you must allow for air to replace lowering fluid levels as your pads/ shoes wear,,

Agreed I shouldn’t have put sealed as the brake system wouldn’t work.

But it does have a restricted access to moisture.

 

[L' Hobo]

Agreed I shouldn’t have put sealed as the brake system wouldn’t work.

But it does have a restricted access to moisture.

Not on some of the earlier Ducato's! /

 

[The Wino]

I remember the braking systems of the 1970,s and the average performance of the cars they were installed in. I wouldn't fancy a modern car with a 1970,s braking system!. As the braking systems have improved it would be surprising if they worked correctly with vintage brake fluid in a similar way I suspect modern engines would struggle run on the old fuels.

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[tonyidle]

I thought it was a sealed system and for water to cause rust requires oxygen?


I do know it’s hygroscopic but the point being made it never used to be a service item.

Similar to all the box ticking done at a “service”

It isn't sealed - there's a breather orifice in the reservoir cap that allows air in and out as the fluid level varies with each push of the pedal. Systems that are totally exposed - motorcycle master cylinders for example - have bellows above the fluid so the reservoir can be sealed. This is possible because fluid volume changes much less in operation and as pads wear. Back in the day when fluid was never changed piston corrosion was much more common.

 

[the1andonly]

Additional info:
the inexpensive (not cheap) pen type testers are "calibrated" to one type only, typically dot 4 and are not suitable for 3,4.1,5,5.1.
There is currently a thread on Fiat forum comparing a Lidl tester versus a professional temperature type (boils the sample).

 

[Garfields]

I have a brake fluid checker, imagine my surprise to see it indicate water in a new unopened tin of fluid.

In all my years as a qualified mechanic in the 60's and 70's, brake fluid was never a serviceable item, what made it so?

At that time brake pipes were steel and unprotected.
Pipes were getting changed for mot at four or five years so flued changed when bleeding brakes.
It had become a service item on the 80's

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