Is there something up with my brake hydraulics?

rev_henry

The other day my dad borrowed my (old) car, and commented that the brakes didn't feel as responsive as they should (or words to that effect) and that I should get them checked - maybe the fluid or the cylinder need. He did then comment that maybe it was just the car being old, he's used to a 56 plate low mileage MX-5 which will always seem 'tight' compared to my 11 year old car.

The brakes work ok, they stop the car, and I know the discs and pads and shoes etc are fine as I had them checked when I bought the car not long ago and the guy said they looked virtually brand new. However, the pedal does seem to travel quite far before it does anything. I don't brake very often at all (I hate the thought of the energy wastage, much better to plan ahead and come off the gas earlier) but when I do the car seems to stop/slow down ok, though having said that I hardly ever brake very heavily.
Is this just me worrying unecessarily (again) or should I get them checked out? Is there some easy test I can perform myself?
I think the brake fluid might have air in and need bleeding, if anything needs doing at all, but I don't really know.
I might add that the car will driven 200 miles or so whilst full of 5 lads plus luggage on Sunday...

skiddlydiddly

Brake fluid is hygroscopic(sp?) so absorbs water.Eventually it needs replacing.It could also as you said need bleeding, something I am quite anal about as I like the pedal nice and firm without having to put my foot through the floor.

I usually bleed from the rear 1st on the opposite side of the car to the master cylinder ie the longest pipe, then the other rear, then the front on the opposite side to the MC and finally the front on the same side as the MC.On abs cars I was told you are supposed to run the engine when doing it but I don't know how much truth there is in this.I have gotten good results without doing so.
I have tried the self-bleeding kits and wasn't that impressed really, I much prefer 2 people doing it.

Edited to add, its much easier to bleed them with a special cutout ring spanner that slots over the brake pipe.You can round the bleed nipple off with an open one and it causes a lot of hassle.If you canno ge th right sized spanner at least buy a couple of new nipples just in case, they only cast a pound or 2.

rev_henry

skiddlydiddly wrote: »

Brake fluid is hygroscopic(sp?) so absorbs water.Eventually it needs replacing.It could also as you said need bleeding, something I am quite anal about as I like the pedal nice and firm without having to put my foot through the floor.

I usually bleed from the rear 1st on the opposite side of the car to the master cylinder ie the longest pipe, then the other rear, then the front on the opposite side to the MC and finally the front on the same side as the MC.On abs cars I was told you are supposed to run the engine when doing it but I don't know how much truth there is in this.I have gotten good results without doing so.
I have tried the self-bleeding kits and wasn't that impressed really, I much prefer 2 people doing it.

Ok thanks for that. I would just take it in and ask the garage but I'm busy with work atm and don't really have time to unless I really need to. Does it do any harm if I don't bleed/renew the fluid then? It will have been done shortly before I bought the car I would have thought.

skiddlydiddly

Not renewing eventually leads to the boiling point of the fluid getting lower so you are more likely to get brake fade.Not really an issue for everyday driving but can happen with a heavy load going down a big hill etc.

rev_henry

skiddlydiddly wrote: »

Not renewing eventually leads to the boiling point of the fluid getting lower so you are more likely to get brake fade.Not really an issue for everyday driving but can happen with a heavy load going down a big hill etc.

OK. Thanks, I will of course get it done at some point but I think its fine for now.

pwllbwdr

Caution: when most people say "brake fade" they are referring to the friction material overheating and losing effectivenes - that's bad enough. But if your brake fluid has too much water in it and has a low boiling point, hot brakes will result in bubbles in the fluid, and possibly no brakes at all.

skiddlydiddly

Yes, I was referring to the bubbles.Not the buildup of gases on the disc surface etc.I've had brake fade a few times and its not pleasant.

anewman

Some brake systems are just poor and/or have brake pedals that give little feedback. Going from a 15 year old Skoda to an 8 year old one was a bit of a learning curve getting used to pressing the pedal less. I imagine if I went back to the 15 year old Skoda now it would feel like there was no brakes, lol. And it isn't that the brakes on the 15 year old Skoda were defective, nearly the whole system was replaced for one reason or another. If they're in good working order and the fluid is renewed as often as it should be I wouldn't worry about it.

rev_henry

anewman wrote: »

Some brake systems are just poor and/or have brake pedals that give little feedback. Going from a 15 year old Skoda to an 8 year old one was a bit of a learning curve getting used to pressing the pedal less. I imagine if I went back to the 15 year old Skoda now it would feel like there was no brakes, lol. And it isn't that the brakes on the 15 year old Skoda were defective, nearly the whole system was replaced for one reason or another. If they're in good working order and the fluid is renewed as often as it should be I wouldn't worry about it.

Thanks, that's set my mind at ease. Well I bought the car in December having had a full service (albeit by the dealer) but prior to that it was serviced every year by previous owner. The book says change the fluid every 2 years, so I think its fine for now.

epninety

I have two more-or-less identical land rovers. Both are mechanically sound and well maintained. The brakes feel very different in them. The daily driver feels like it has very poor brakes when you jump into it straight from the other one.

Both are easily capable of locking up the wheels, and stop straight. The difference is mainly down to the brake pad material fitted in each one, and to a lesser extent condition of all the other variables - discs, brake fluid, flexi hoses etc.

In short, if it stops in a straight line, and quickly, it's probably OK.

As I recall, the usual first checks for home mechanics are :-

If you stand hard on the pedal while stopped, it should sink to a point then stop, not continue to the floor - indicating no leaks in the system (fluid or vacuum).

Pump the pedal with the engine off, until the pedal feels like a board. Then with your foot on the pedal, start the engine. The pedal should sink a little as the vacuum servo pumps itself up. (The important thing is that you feel the pedal sink as the brake servo charges up, not how much it sinks especially.)

Check for straight line stopping using moderate braking effort on a flat dry road (with no traffic on it!)

Past that, you really need a friendly garage to give it a quick check on the brake tester, or pop in teabreak with a packet of biscuits and ask them to give a it a quick testdrive.

And that's a proper garage - a place where mechanics work - not the local fastfit centre :rotfl:

Inactive

Find a quiet road, make sure there are no vehicles behind you, then try pumping your brake pedal, if the footbrake pedal travels less distance on the second press, it usually indicates some air in the system that would be rectified by properly bleeding the brakes.