Brakes & pedals

[mike123]

I have a couple of questions about the brakes and pedals... thanks in advance for any sage advice anyone can share!

First, I am really surprised at the brake functionality. It feels like I'm stopping a freight train. The brake pedal takes a very strong push to get to its full stopping power, and even at what seems to be the full stopping power, it seems pretty poor. Most threads describing brake issues seem to be referring to "spongy" brakes, but that isn't how I'd describe what I'm feeling. It feels like the pedal is very stiff, and that pushing hard just doesn't translate into pads gripping the disc strongly. Just curious if "they're all like that" in the DeLorean, or if there is something that can be improved on mine.

In terms of diagnosis, my brakes were checked out recently and I was told the pads were good, the calipers were good, and the rotors were at .500 and .497. I was told there is a significant vacuum leak in the transmission hose, but I don't know if that's related to the brakes at all.

Second and totally differently (but didn't want to spam with multiple threads), I was wondering if anyone has adjusted the brake and gas pedals or even the length or angle of the pedal arms in their car. In my Corolla, the brake pedal is 5 1/4" from the floor mat, and has a 2 1/4" gap to the gas pedal. In the DeLorean, it's 4 3/4" from the floor mat, and 1 1/2" from the gas pedal. The gap between them is the primary issue; I wear a size 9 shoe but moving from a depressed gas pedal, I am often clipping the brake pedal as I bring my foot up off of the gas to move to the brake pedal.

[WHO1DMC]

My first guess would be not enough vacuum or a bad brake booster. Since you said you have a vacuum leak that's were I would start. As for peddles. I think most have problems with them. They are very close together. It takes me a little time to get use to them again after a new pair of shoes.




Dave B.

[DMCMW Dave]

My first guess would be not enough vacuum or a bad brake booster. Since you said you have a vacuum leak that's were I would start.
Dave B.

I'd agree. Brake booster failure was usually considered pretty rare, but the rubber parts inside aren't getting any younger and I'm sure failure is getting more common. You should be able to hear vacuum hissy noises near the booster if it's gone bad inside.

I've seen the small check valve at the booster fail, and if the car has been apart/engine out/frame off it's possible someone kinked the hose that goes to the booster. It's a metal pipe along the frame but there are rubber sections at each end. If the hose is completely disconnected its a huge vacuum leak, enough to impact the running of the engine.

[David T]

I'd agree. Brake booster failure was usually considered pretty rare, but the rubber parts inside aren't getting any younger and I'm sure failure is getting more common. You should be able to hear vacuum hissy noises near the booster if it's gone bad inside.

I've seen the small check valve at the booster fail, and if the car has been apart/engine out/frame off it's possible someone kinked the hose that goes to the booster. It's a metal pipe along the frame but there are rubber sections at each end. If the hose is completely disconnected its a huge vacuum leak, enough to impact the running of the engine.

I agree you should start with the vacuum booster and vacuum lines. It can also be the pads are glazed because they were not broken in properly. Break the glaze on the rotors by sanding lightly with a 3" 100# pad mounted on a drill and go around in a random pattern. For the brake pads a light sanding should do. Avoid panic stops for a while.

[mike123]

Thank you for the help! I will look into the vacuum and brake booster as potential causes. It's great to hear that it sounds like this is not the way they all are!

Will take a look at the pads as well, but I think the issue starts at the pedal.

Speaking of the pedals, I am going to look into some sort of solution for getting them to have a wider gap between them. Will update the group if I get anywhere successfully with that.

[jangell]

Second and totally differently (but didn't want to spam with multiple threads), I was wondering if anyone has adjusted the brake and gas pedals or even the length or angle of the pedal arms in their car. In my Corolla, the brake pedal is 5 1/4" from the floor mat, and has a 2 1/4" gap to the gas pedal. In the DeLorean, it's 4 3/4" from the floor mat, and 1 1/2" from the gas pedal. The gap between them is the primary issue; I wear a size 9 shoe but moving from a depressed gas pedal, I am often clipping the brake pedal as I bring my foot up off of the gas to move to the brake pedal.

You get used to it. I was constantly hitting the edge of the brake when moving to the gas, but now I'm used to it. I have size 11 shoes. It just takes some practice. But I will say that the DeLorean gas pedal does seem unusually close to both the brake and to the center transmission tunnel area thing to its right, which leaves a fairly small window to accurately put your foot in.

I haven't looked into what is involved in actually moving the pedals around. Given that the brake pedal directly pushes on the brake booster with a rod (I think), it seems like it would be not exactly trivial to move it, and if you can't move that, you can't move the brake either.

-- Joe

[mike123]

But I will say that the DeLorean gas pedal does seem unusually close to both the brake and to the center transmission tunnel area thing to its right, which leaves a fairly small window to accurately put your foot in.

I haven't looked into what is involved in actually moving the pedals around. Given that the brake pedal directly pushes on the brake booster with a rod (I think), it seems like it would be not exactly trivial to move it, and if you can't move that, you can't move the brake either.

-- Joe

Here's my size 9:
PXL_20230712_001518936.jpg

Small window is an understatement! The shoe is flush with the center tunnel wall, and has around 1/8" space before the brake pedal. I didn't realize quite how tight it really was until I took this picture.

I'd be up for hacking off the right side of the brake pedal, or cutting off the whole pedal and re-welding back on so that the pedal pad is more to the left. But will give it some time to try to get used to it first.