66polara

Never been on a forum before so here goes. We have a 66 polara conv that I just love, bought it last year and am still working some of the bugs out of it but it's still a good driver. Trying to figure out if my rear brakes are overheating, the drums on mine get up to 300 deg after 30 miles or so is this normal/high normal for a car this size? It had a front disc conversion done a yr before I bought it w minimal use. The rears have been completely rebuilt, new drums turned etc. Booster wasn't holding vacumn so I just replaced that.

fivepoint

Nice looking car. That temp does seem high. Do the rear wheels feel like they are dragging when you turn them by hand? Make sure the parking brake is fully released. If they turn fairly free, then maybe the front brakes are not working as good as they should. When the fronts were converted to disc, was a proportioning valve installed? If so, was it adjusted properly?

RacerHog

Unless you are a aggressive stopper or doing a lot of down hill braking... Yes that is too hot... That is almost the verge of boiling Dot3 brake fluid.... and you may see a spongy brake pedal when it gets that hot?
I would have to say that the brakes are not working correctly for some reason... Just my 2 cent...
Nice ride... Welcome to the site.... We all were newbies to these sites at one point or another.... Just on in here... We dont bite !!!!

66polara

The front disc conversion was done by a performance shop that does lots of these so I can only assume they were set up properly. There is a proportioning valve and an adjusting valve after the proportioning valve. I measured the pushrod from the power booster it seemed to be 4.5 mm to long so I spaced off the master cylinder but still the same. Going to find someone local that does these front disc conversions and let an expert have a look. I have backed off the parking brake and not used it so that shouldn't be a problem. Thanks for your replies and trying to help me out

fivepoint

Keep us posted on what you find. Have you tried to lock up the brakes on an empty parking lot and see if the fronts lock up?

66polara

I have a friend that is a mechanic who's going to look at it. There are times when we need to let people who are experts do what they are expert at, and the brakes on a 4000 lb car is one of those things. I will keep y'all posted on what he finds out

66polara

This has turned out to be much more than I thought. The front disc conversion that was installed a year before I bought the car had a faulty power booster that would not hold vacuum and it turns out a master cylinder that was keeping pressure on the rear brakes also what we thought was a proportioning valve was actually just a splitter with a pressure adjusting valve behind that for the back brakes. I am an electrician by trade and when we buy parts they very rarely fail however I have found that buying parts for old cars are not always reliable just because they're new. Took the car for a ride last night checked temperature max temperature I got on the outside of the drums was 230 degrees but it never crept up past that and the wheels and rims didn't get hot like they used to. Also the brakes are not grabbing at slow speeds when coming to stop like they used to when they would heat up. I appreciate everyone trying to help me out

fivepoint

That's great. You can really enjoy the cruise when all is working properly. Safe travels.