Brake Fluid?

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Hi peeps I wondered if you could help, I am geeting my brakes bled this week, can I use dot 4 brake fluid on my elan or does it have to be dot 3?
Kind Regards

Andrew

[bobbrown]

DOT 3 ? thought the standard system was DOT 4
In any case if running DOT 3, DOT 4 or DOT 5.1 the fluid should be changed every couple of years and the major differance is temperature.
All are Glycol-based
DOT 3 Dry boiling point 205 °C Wet boiling point 140 °C
DOT 4 Dry boiling point 230 °C Wet boiling point 155 °C
DOT 5.1 Dry boiling point1 270 °C Wet boiling point 190 °C

Do not confuse DOT 5 with DOT 5.1 DOT 5 is Silicone-based and can not be used on a system that has had a Glycol-based fluid in it.

There should not be any problems going to DOT 4 or DOT 5.1 as long as the system is flushed.

Bob

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Thanks bob

[DeanG]

Replacing the brake fluid is good practice. After one auto-cross run where I used a lot of left foot braking while hard on the gas I opened the hood and there was a fountain of brake fluid coming out of the master cylinder reservoir. That let me figure out that this is what had eaten up the foam pad on the hood.

[RayD]

Out of interest Dean ... what brake set up do you have to make left foot braking advantageous in a Lotus Élan?

Ray

[DeanG]

I have the stock rotors. I can't remember what pads were on the car at the time.

Anyway when I was young and foolish I drove my 1978 VW Scirroco hard. I read about the SAAB rally drivers using left foot braking and while applying power with the right foot to balance the car in curves. The idea is that the brakes remove some of the torque going to the front wheels unloading the tire and allowing it to turn better. The brake force on the rears loads the tires and makes them slip a bit more. So less understeer. It actually works well when the car is on the edge. Crazy doing this on the street but like I said I was young and foolish. It is especially helpful with trubo cars because you can eliminate the turbo lag by getting the turbo spun up before you would normally be getting on the gas.

At one of the LOGs the autocross was on a huge asphalt lake. Part of the course was a full circle of 200+ ft diameter. On the big circle part I played around with power on, power off, left foot braking pressures and throttle application. It was a load of fun and it was easy to feel the car transition from oversteer to understeer and back. For me it is easiest to feel this by getting a large constant radius turn and adding power until you get a bit of understeer. Then gently add brake and feel the car start to turn in. The nice thing about this technique is that it works great on slippery surfaces like dirt or grass. Unless you really screw up, like not having sufficient runoff room when practicing the worst that happens is that you go slow. It does take a heavy toll on the brakes.

[Ted]

Hi all,
I have questions. SJSPORTSCARS sells silicone brake fluid. Does the brake fluid has to be silicone based on the Elan?
And, how can you know if the brake fluid in the brake system was silicone or not? I bought my Elan last year, and have problems with my brakes. So I bled the brake system many times with full synthetic fluid (RBF600). Could it have ruined some things if I had silicone in the car?
My pedal is smooth and no feeling, I wonder if I could have the master cylinder or the servo dead.

[rip]

DOT 5.0 is silicone & is known to attack some rubber seals. I have never seen it on sale.

DOT 3 is mineral.
DOT 4 is synthetic. DOT 5.1 is synthetic & has been approved with a higher boiling point than DOT 4.

DOT 3 is probably OK for our cars too but not as easily available as 4 or 5.1. You may want it for an older classic, but for an Elan, DOT 4 & 5.1 are fine.
RBF600 is DOT 4.

[dapinky]

DOT 3 is probably OK for our cars too but not as easily available as 4 or 5.1. You may want it for an older classic, but for an Elan, DOT 4 & 5.1 are fine.
RBF600 is DOT 4.

brake fluid label.JPG

Whilst DOT 3 will be physically compatible with the OE DOT 4, it will have a lower boiling point, so please don't use it.

I'd be surprised if you can still easily buy DOT 3 anyway, and you can't go too far wrong with DOT 4.

DOT 5.1 is okay for a top-up if you have some to hand, but offers few real advantages over DOT 4 (and is remarkably expensive for what it is) - good for racing applications, but not necessary for road use.

The main thing is to not mix mineral and silicone based fluids - they wont mix!

The way to see if you have DOT 5 already installed is to see what your decal by the right side bonnet hinge says - if the fluid was replaced by anyone worth their salt, then the original decal will have been removed and/or replaced to indicate the change....

...as Iain says, DOT 5 can cause problems with SOME rubber components, but all of the ones in an elan should work with it - BUT ONLY IF THE SEALS HAVE ALL BEEN REPLACED WHEN THE FLUID WAS SWAPPED OVER.

If you decide that you'd like to use silicone fluid, then it will need a complete strip/rebuild of the whole system - your choice!

The real advantage of DOT 5 is that it isn't hydroscopic, so will not absorb water over time - so doesn't degrade over time, and lasts a bit longer as it doesn't need to be changed so regularly.

Personally, I think it's unecessary on anything other that a 'proper' competition car, and you're far better off using DOT 4 and changing it regularly in accordance with the Owners Manual servicing guide (which many don't bother with!).

The best place to get your fluid from is Halfords - they will sell you a 5L container for 18 quid - smaller containers are availlable for topping-up, but are only a couple of pounds cheaper than a big one

A container that size will see you right for 2 complete changes, and the odd top-up in between (which if it's necessary, indicates a bit of a problem somewhere anyway, which will need addressing!).

As an easy check to see what you have at the moment, dip your finger tip in the reservoir, and then stick it into water - if it dilutes and washes off it is NOT silicone, if it forms 'balls' or 'bubbles' (not mixing with the water), then it is DOT 5.

[Fredjohn]

Think Ted may struggle to get anything from Halfords as he lives in France.

However, Ted, stick with the recommendations of Dot 4 or Dot 5.1, read your label and do not mix silicone with mineral.

Both are readily available in France (I know because I had to buy some to keep the brakes working on a 2000 mile trip to France 2 years ago!) and are identified in the same way.

Bonne route!

[dapinky]

Think Ted may struggle to get anything from Halfords as he lives in France.

Good catch, John - I missed that bit

[Ted]

Thanx guys.

I always put DOT4, but as I have a bad feeling with the brakes, I wondered if something could have being injured by some silicone fluid.