Poor Fuel Economy? Read this!

[BlazerLT]

Ok, so my fuel economy has been suffering for a couple of month and I thought it was because of the cold...I was wrong.

Turns out AFTER my front brake replacement which included new pads, and the guide pin lube....my economy has recovered...SIGNIFICANTLY!

From 15MPG to 20MPG in one tank. Same fuel,,,,,same station.

From what I saw, the caliper pins were lacking any lube at all thanks to the frucking garage not bothering to lube them when they replaced my calipers. This lead to them not disengaging properly when replaced and I guess they were sticking on a bit.

The pins I completely lubed with the left over moly grease for the pad shims and I gave them a good fine smearing all over BUT, don't put grease on the threads.

Since then, the calipers have been releasing perfectly and the above fuel economy gain was seen.

This should be part of your yearly maintenance routine. Simply remove the pins, lube, and reinstall. The grease will stay on for a long time. Will take about 5 minutes per side.

I know I have learned from this and I am happy to see a 50mile jump per tank of fuel.

This was the only thing changed, I am sharing this so you won't prematurely wear out a caliper and a set of brake pads like I did before I caught it.

MY help and 0.02.....

[kb3jhp]

i had the same prob if i would get on the brakes hard they seemed to get slightly hung up and ran a littel hot

[muddog321]

98up the rears are even worst because the slides are actually diff and most only take the caliper retainer bolts out and never pull the slides in the bracket out. When those freeze up it eats the rotor quickly.

[OverBoardProject]

Thanks for the tip BLT, I'll do mine when I rotate my tires soon

[BlazerLT]

No problem, I will do the same, makes a world of difference in the braking smoothness as well.

[JimmyGold]

Is the new 20 mpg with or without acetone?

[BlazerLT]

Without.

[JimmyGold]

Cool...maybe you'll give us an update with the acetone now that it's warmer?

[BlazerLT]

For sure, I plan on doing that soon.

[old_master]

Blazer LT,

Sounds like you found some rookies at that garage. Every brake technician should know that the hardware, guide pins, boots, and retainer clips should all be replaced and lubed with every brake job. Rust needs to be removed from all mating surfaces on the pads to the calipers, calipers to the knuckle/spindle, and rotor to the hub. Rotors must either be machined or replaced. There is a huge misconception that brake pulsation is caused by rotor warpage, not the case. It is caused by metal transfer of the pads to the rotor surface when the vehicle comes to a complete stop after a hard brake application. Binding hardware essentially does the same thing by leaving the pads in tight contact with the rotors. Brake pulsation was virtually unheard of prior to the 70's with organic pads. True, resurfacing the rotors cures the pulsation, only because it removes the embedded metal from the rotor surface. The pulsation will continue to return until driving habits are changed. After a hard brake application, only apply enough pressure to hold the vehicle after stopping. Caliper pistons must retract easily & smoothly back into their bores. A product called "Sil-glide" works extremely well on the hardware and all mating surfaces of the pads and calipers. Sil-glide will stand up to the heat better than the moly grease. Before you install the wheel, put one hand on the caliper, it should slide in and out VERY easily. A little dab of anti-seize on all threaded fasteners helps the next guy out when it comes time to service it. Ya never know, the "next guy" might be you. Those rookies probably cost you more on fuel than the few bucks involved to do the job correctly. Most consumers think the technician is trying to rip them off when they tell them they need all new hardware etc; you experienced a perfect example of why it's needed. Bottom line, do an inferior job...expect inferior performance. Glad to hear you have it under control.

[blazee]

Originally Posted by old_master

Blazer LT,

Sounds like you found some rookies at that garage. Every brake technician should know that the hardware, guide pins, boots, and retainer clips should all be replaced and lubed with every brake job. Rust needs to be removed from all mating surfaces on the pads to the calipers, calipers to the knuckle/spindle, and rotor to the hub. Rotors must either be machined or replaced. Caliper pistons must retract smoothly back into their bores. A product called "Sil-glide" works extremely well on the hardware and all mating surfaces of the pads and calipers. Sil-glide will stand up to the heat better than the moly grease. Before you install the wheel, put one hand on the caliper, it should slide in and out VERY easily. A little dab of anti-seize on all threaded fasteners helps the next guy out when it comes time to service it. Ya never know, the "next guy" might be you. Those rookies probably cost you more on fuel than the few bucks involved to do the job correctly.

It may not have been rookies, a lot of places have taken up the practice of merely doing a "pad-slap". They only change the pads and do nothing to the rotors or the hardware. This is a terrible practice and only leads to more expensive repairs later on.

I usually service brakes the way that you described. I also wash the rotors in dishwashing liquid after putting them on the lathe. I've been using the permatex brake quiet spray on the back of the pads. I tried the permatex silicone guide pin lube the last time a did my brakes, it seems to be pretty good, but I won't know for sure until I tear them down again.

[old_master]

Pad slapping was fine years ago with organic pads. With semi-metallic, ceramic, carbon metallic, or any of the other new friction materials on the market, you're right, you're asking for problems. Dishwashing liquid after machining and a non-directional finish is a great idea and works extremely well. Get good quality pads, ones that are slotted and chamfered and have stainless steel shims riveted on, and you can toss that spray can. Avoid the pads that don’t have all three.

[nickledimed]

Well. I disagree with this idea of changeing all the hardware and machining the rotors at every break job. I have been a machinist for about 20 years and I do my own breaks. I have only had to machine a set of rotors once and thats becouse they were warped. Ive been doing my own breaks since I was 14 and I beleive that if the rotors are not warped or had metal to metal contact, they do not need to be turned. this miss conception was started so that break shops could make more money. I know, my grandfather own a shop and thats how I learned to do breaks. As for the metal imbeded into the rotor? ...give me a break even after you machine the rotor and wash it, the first time you apply the break guess what?....youve got metal imbedded in the rotor again, plus, its brass so I realy dont think it gets inbedded into that very hard rotor, at least not that i have seen.
oh yea........dont forget to change the air in your tires every 3000 miles..and dont forget the blinker fluid too.....lol

[BlazerLT]

Originally Posted by blazee

It may not have been rookies, a lot of places have taken up the practice of merely doing a "pad-slap". They only change the pads and do nothing to the rotors or the hardware. This is a terrible practice and only leads to more expensive repairs later on.

I usually service brakes the way that you described. I also wash the rotors in dishwashing liquid after putting them on the lathe. I've been using the permatex brake quiet spray on the back of the pads. I tried the permatex silicone guide pin lube the last time a did my brakes, it seems to be pretty good, but I won't know for sure until I tear them down again.

I think it is just a bunch of high performance work done fast and not complete.

When they initially did this job, they replaced the calipers as well. BAD idea!

The calipers were AC delco on it and they put some remanufactured junk on it. What a stupid idea. That is what probably caused the one caliper failure on the passenger side.

But man does it run nice now. And the fuel economy seems to be up and staying up in a big way. This could have been causing the pinging to seeing the engine had to work harder and was under load constantly.

If you want something done right, you do it yourself I guess. These asshats will never get my money again. Shitty work.

BTW, the caliper pins seemed to be rather pitted, should I go and get some new ones?

[BlazerLT]

Originally Posted by nickledimed

Well. I disagree with this idea of changeing all the hardware and machining the rotors at every break job. I have been a machinist for about 20 years and I do my own breaks. I have only had to machine a set of rotors once and thats becouse they were warped. Ive been doing my own breaks since I was 14 and I beleive that if the rotors are not warped or had metal to metal contact, they do not need to be turned. this miss conception was started so that break shops could make more money. I know, my grandfather own a shop and thats how I learned to do breaks. As for the metal imbeded into the rotor? ...give me a break even after you machine the rotor and wash it, the first time you apply the break guess what?....youve got metal imbedded in the rotor again, plus, its brass so I realy dont think it gets inbedded into that very hard rotor, at least not that i have seen.
oh yea........dont forget to change the air in your tires every 3000 miles..and dont forget the blinker fluid too.....lol

This is partially true, you don't have to, but it is best to do so seeing even rotors are cheap.

I myself just slapped on new pads.

These Monroe pads are excellent, I highly recommend them.

No brake dust at all, stainless steel shims and grease for those shims to boot.

Best money I have spent in a while, and they were even 25% off.

SCORE!