Wilwood brake ugrade on my mk4

[Melb-Mike]

I finally finished my Wilwood brake upgrade, My MK4 that I recently bought had the stock 86-93 Mustang brake rotors, and without a brake booster, made braking a scary situation. You sure didn't want to tailgate anyone. I bought the mid-grade Wilwood kit from Gordon Levy Racing. Since I don't plan on doing any high speed track events, Gordon recommended this kit.

My wheels are Cragar SS 17" diameter wheels so caliper clearance wasn't a problem. Even so, the $2300 tab to get better braking isn't a minor expense. However, it got worse. I then found out the Roadster had the pre-94 front spindles and the Mustang lower control arms. The Wilwood kit needs the newer spindles and that mandates the FFR lower control arms. I found rebuilt SN95 spindles on EBay for around $300. The FFR lower control arms added another $440. I decided to replace the master cylinder with a similar bore (15/16") but went with the 95 Mustang Cobra unit from Rock Auto Parts for $75 shipped.

So now I'm a little over three grand on the upgrade. I also decide to use DOT 5.1 silicone brake fluid. If I was racing it, I'd use DOT 4 Motul RBF 600 but this is a street cruiser only so durability was my major concern. The nice thing about the newer master cylinder is my power brake bleeder fits right on the plastic reservoir which makes bleeding a lot easier. Silicone is a bit heavier viscosity than regular brake fluid so bleeding is a bit more time consuming.

Well now the results. FANTASTIC. Rock hard pedal, very responsive brakes with a very linear response that is very predictable. No ABS here, no booster either, just you and the brake pedal. I am very pleased with the kit and how the brakes work now.

Downside: Gordon had told me he would make Parking brake cable brackets. None were provided and my email request regarding getting either the bracket or a drawing or picture if the bracket went unanswered. Customer service is a little lacking. No instructions at all on any of these parts, you are totally on your own.
However, everything fit and worked very well, and the results are great !!

Mike

[Gordon Levy]

I'm glad your brakes are working well. I did email you pics of the rear brakes assembled and of the support brackets. Sorry I didn't make some but i haven't in over 10 years because many wanted to do it a different way. I tell everyone that when they purchase the kit. As you said it went together very straight forward and I am only a phone call away if you need help.

[Melb-Mike]

The very important thing is how well these new brakes work. I'm impressed with the improvement. They feel like I have power brakes. I'm one happy camper. I never got the picture but maybe your email got blocked by the firewall. I've sent emails that never got there too.

By the way the thing that amazed me if even though I don't have a proportioning valve, none is needed. Balance is perfect. Thanks Gordon for your recommendations, it did the trick.��

[Gordon Levy]

Glad you like it.

[Avalanche325]

I also decide to use DOT 5.1 silicone brake fluid.

DOT 5.1 is not silicone, it is glycol based. It is also low viscosity (thinner) than 3 or 4. Good fluid with a higher boiling point than standard 3 or 4. The high performance DOT 4 fluids can have a higher boiling point than 5.1.

DOT 5 is silicone. You REALLY do not want to use this stuff on a street car. The good quality is that is doesn't absorb water. That sounds wonderful. Except that water still gets in the system but stays separated. This causes little pockets of water that boil and cause a soft pedal. It also causes rust in the system. OK for a serious race car that is going to change out the entire brake system every year. But not much else.

[PeteH]

I have to take exception to your statement about DOT5 silicone in a street car. I have been running it in my big Healey for 20 years, and that car has been driven all over t he Midwest and east coast. The TR6 for 10, MGB for 6 yrs, and a 71 Honda CB 750 for 13 yrs without any issues whatsoever. No sign of moisture when bleeding, and the fluid is as clear as when I put it in, no degradation of the elastomer cup seals. It is more difficult to bleed as the bubbles stay dispersed more, but works great from my experience, and it does not blister paint.

[Melb-Mike]

I made a mistake when I said DOT 5.1. It is DOT 5, silicone brake fluid.

Avalanche325 is correct when he states that water will lay on top of the silicone fluid, it doesn't mix with the fluid. However, think about the brake system. There is no air in the system once it is completely bled. The only place where water could lay on top of the fluid is in the master cylinder reservoir, and it's plastic. The lines and calipers are all a closed system so water contamination from condensation won't happen.

I've been using silicone brake fluid a while back after having to replace the calipers on my 69 Corvette. I now have it in 6 or 7 of my cars and will convert all the others at every opportunity, except for my Lotus and Porsche. The Lotus uses Motul RBF 600 racing brake fluid (DOT 4). The 911 TT uses proprietary Porsche fluid on X50 optioned cars, according to Porsche. That could be a bunch of BS, not sure.

So far I would have to say silicone brake fluid equals any brake fluid in braking performance. Also, and this is very important, spilled silicone brake fluid on any paint doesn't cause damage. ��

[rich grsc]

Dot 5 nowhere near my car.
https://www.youtube.com/watch?v=7gSchzhcslc

[Melb-Mike]

Yes, I watched the video. I may have to rethink the DOT 5. Strangely enough this is the standard brake fluid for military vehicles. One of the guys around here buys and restores military 6X6 trucks so I asked him if he ran into issues with the silicone brake fluid in any trucks he's rebuilt. He told me the older vintage military trucks didn't all have silicone. Some were converted over like the newer vehicles. He never had much issue as a result of the fluid or with the fluid's retention of water. He even refills the brake system with it. So I don't know which is best. The nice thing about the fluid not mixing with water is you can more easily bleed out any water in the calipers by using the bottom bleeders on the Wilwood calipers. There are only two places water could accumulate, the bottom of the reservoir of the MC or the caliper.

Another way of looking at this is to think of the brake system as a simple hydraulic system. Hydraulic systems use hydraulic fluid which is predominantly AWS 46 or AWS 68, pretoleum oil. It doesn't mix with water and water goes to the bottom as well. Apparently this hasn't kept bull dozers, front end loaders, cranes, dump trucks or backhoes from working for many years. Maybe the YouTube video is accurate but hyping the issue.

[Melb-Mike]

I posted the question of "SILICONE BRAKE FLUID -GOOD OR BAD ?" on my Corvair forum to see what the ecoeriences were. Since Corvairs are old cars, and their owners are generally older too, I figured I woukd get good long term experience stories on Silicone vs DOT 3. Nobody, let me repeat, NOBODY reported any corrosion or rust problems even after 20+ years of use. There was concern regarding its use in high altitude places like Pike's Peak. A lot of car owners use it. I'm sold on it.