My headers are boiling the brake fluid

I have a '69 GS400 with a 462/thm400 , 4 wheel, power drum brakes. Hooker Supercomp full length headers (inside the frame rails). The headers are too close to the distribution block (frame mounted) and the brake lines. When in stop & go traffic on a hot day the headers cook the brake fluid causing little to no brakes. I know the solution is to move the distribution block and lines. Has anyone completed this change and can suggest other block locations and line re-routing paths. Do any kits exist to make this a painless job? Pictures of where you relocated everything would help me a lot. I really don't want to make this look like a sloppy mess.

Thanks for any input you may have.

Jay

 

I've had Buicks with headers for years and thousands upon thousands of miles and never experienced boiling brake fluid? You sure that's what's goin on. But if that is the issue, Inline or Classic tube can provide you with what I call the "Chevy" mount location it pits the prop valve up by the master cylinder, you would just need to extend the the line to the rear to meet up to the new location, the other lines would be plug and play pieces

 

Without a doubt. I only experience the brake fade in bumper to bumper slow, stop and go traffic when the weather is HOT, never in normal traffic, even in HOT weather.

There is less than 1/2" between the header tube and distribution block and where the line crosses over the engine crossmember and passes the rear header tube on both sides,

I have a piece of welding blanket wrapping the distribution block , (effective) but it looks pretty cheesy tied there with bailing wire! Really no way to do that to the lines.

 

Do you have Ceramic coated headers? That may contain the heat just enough to negate this problem. Don't know, just thinking out loud.

 

Larry - I think your 70 has a different distribution block setup than our 69's

.. Jay - the block has a mounting bracket it is bolted to - I removed that and drilled/screwed just the block to the frame. Yeah, it may have only gained me another 1/2" or so .. but that could be your fix. Mine are TA headers so perhaps I had a bit more clearance to start but going from memory when I installed the headers almost 20 years ago I think the block was basically almost touching the headers (and yes, they are JetHot coated)

 

I've seen this in Chevy powered sightseeing bus chassis : usually 5000 or 6000 chassis. These were used in center city driving . I cured it by putting a shield between the brake lines and the exhaust manifold . It was just a piece of metal to reflect the heat . Worked great. You probably can get a little more clearance from the block and header with a little bit of prying

 

My car is a 70 with Poston headers but I swiped my disc brakes from my 71 skylark doner. While I had the body off the frame I noticed that the prop valve nearly touched the header primary and just like Alan did I pulled the standoff bracket off and bolted it direct to the frame. This gives you at least a bit of clearance, and I've had no problems with brakes. If it is still an issue after that then see about getting some heat shield material from DEI engineering to isolate it further of maybe look at wrapping that header primary where it's close to your prop valve.

 

Thanks for the suggestions guy's, I'll look again but I'm pretty sure the distribution block is tight against the frame. I did consider wrapping the 1 tube but, I was concerned that wrapping just 1 tube would be a problem.

 

I don't know what problems wrapping one tube would cause but I bet it's less trouble tha you currently have with crappy brake performance. If it were mine I'd start with some heat shielding between the block and header tube and maybe do a brake fluid flush and fill to one of the higher boiling point DOT4 fluids. This would be relatively cheap and easy. Besides if you actually have boiled the fluid then you probably should do a flush and fill (bleed) anyway...

 

If you bolt it directly to the frame, you should gain a little clearance and the frame will act as a big heat sink to dissipate the heat.

 

A fluid flush and fill is absolutely in the plan after overheating the fluid.