Brake Fluids?

Chat and banter about Minor LCV's
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womble3go
Posts: 10
Joined: Sun Nov 02, 2014 7:56 pm

Brake Fluids?

Post by womble3go »

Just about to finish replacing most of brake system on the 4door which fluid to use DOT 4 or the DOT 5 (silicon-based)? any one else done this would it would with seals? Only some of the pipes not changed.

les
Posts: 598
Joined: Fri Oct 31, 2014 4:45 pm
Location: kent

Re: Brake Fluids?

Post by les »

I use silicon fluid, my rebuild included all new seals and flexible pipes. If you’ve replaced most of these parts, replace the remaining few and go for it, silicon has served me well.

Boxofbits
Posts: 365
Joined: Sun Jan 10, 2016 9:47 pm

Re: Brake Fluids?

Post by Boxofbits »

I used DOT 5 Silicon on my Triumph but have heard on the Triumph forum that DOT 5 is not really compatible with rubber seals used in our braking systems. Apparently it swells the seals after some time jamming on calipers, brake wheel cylinders etc.

One restorer on there will only use DOT 4 which I will next time. DOT 5 was developed for the US military as it is not hygroscopic so doesn’t absorb moisture, which is one benefit, but has cons also! During a long run in my Triumph TR4a the O/S Front caliper did partially seize after changing to DOT 5, but which I managed to free off, so can’t conclude if this was due to silicon fluid.

Kev

les
Posts: 598
Joined: Fri Oct 31, 2014 4:45 pm
Location: kent

Re: Brake Fluids?

Post by les »

I’ve been lucky then! I put silicon in my pickup around the year 2000, and have so far had no issues.

Keith 66
Posts: 3
Joined: Sun May 12, 2019 9:04 pm

Re: Brake Fluids?

Post by Keith 66 »

I rebuilt my pickup back in 91, as i had replaced everything i put Dot 5 fluid in. I had read that "The brake pedal feels different" but that was all. Now my wife & i had owned a succession of elderly moggy vans before this & replacing a slave cylinder on one corner or another was virtually an annual occurence come Mot time. Steel pistons in Ally cylinders on the back & Iron cylinders with ally pistons on the front is a recipe for corrosion anyway never mind adding hydroscopic brake fluid.
The pickup went on the road & served as my everyday boatyard truck for the next 17 years. In that time the only time i had to bleed the brakes was when i had to replace the hydraulic brake light switch as it broke & i had to break into the system.
The truck was laid up for another 7 years, Upon uncovering it to move into the shed for its next restoration the brakes still worked. No seizing they just worked. If you open up the master cylinder reservoir the fluid is as clean as the day it went in. This experience is good enough for me & with the cost of replacement brake cylinders its a no brainer.
By the way thanks to Russ for getting me back on here!

midget
Posts: 90
Joined: Sun Dec 14, 2014 12:48 pm
Location: Wantage

Re: Brake Fluids?

Post by midget »

Yep, I can second those positive comments above.
Just put mine back on the road after extensive rebuild including all brake parts and dot 5 silicone fluid.
The only difference seems to be that it needs a firmer push on the pedal, but I did also fit discs at same time ,so maybe this may be something to consider?
John

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