1990 Accord LX Auto. Shaking at idle, brakes shakes, pump brakes at stop light.
 

Thanks for any help in advanced.
I used to own a 92 LX in the 90's. I havent really worked on a car, other than oil/brakes(pads and rotors)/lights/radio.
I just got this car from my wifes grandmother to keep the milage low on my other car.

I was told that they did a tune up last year.

1. Shakes at the top of braking and almost goes away as I press more onto the brakes. I suspect bad spots on the rotors. Any other ideas?

2. The care turns on great little shaking. But when I throw it on reverse. It shakes violently until I add some gas and shakes again as I ease up on it. I suspect the engine mounts but haven't gone down and checked them. Any other possible ones?

3. When I sit at a light, I noticed I have to pump the brakes, I feel like It looses presure and the brake pedal gets to the floor and I have to lift and press again. I suspect the master cylinder. I don't see any leaks. And can this be related to 2.?

Again, thanks in advanced. I'm really glad to be back in an accord.

1) New front brake pads and rotors are likely the fix. Warped rotors is the cause of pulsation under firm braking. I've also felt pulsation w/ light braking that went away under heavier braking. Same fix as far as I know.

2) You can inspect the motor mounts by setting emergency brake and foot brake firmly w/ helper while you observer from passenger side of car (care is necessary!). First put into D and pulse the throttle to 1500-2000 rpm while watching the front mount. Any damage should be obvious.

Similarly, shift to Reverse and again pulse throttle while observing rear motor mount w/ light from passenger side (under the throttle body). Excess movement up/down and damage should be seen if mount is damaged.

3) Symptom of internal leak on brake master cylinder, or external leak anywhere. If not loosing any brake fluid, the MC is passing fluid under pressure allowing pedal to go slack.

good luck

1) I've sometimes fixed it with hard braking. This doesn't always work but it's easy & only costs your fuel. Same as bedding-in a new set of brakes, so do this again if you end up replacing the brakes.

Find someplace where you can do this without being stupid in traffic.

Hard braking 3 or 4 times from about 30 or 40 down to about 5 mph. DO NOT STOP - keep driving about 5 minutes inbetween to let them cool before doing it again.

More hard braking (almost lock-up the wheels) from 50 or 60 this time. Don't stop, let em cool 6 or 8 minutes in between.

What you're doing is transferring some hot brake-pad material onto the surface of the rotors. Shaking brakes is usually caused by this happenning UNEVENLY around the surface of the rotor. So the rotors aren't really warped, they just have areas with more or less friction.

This is made worse by braking hard in traffic, then holding the brakes clamped at a red light. The open area of the rotors cools down while the part being clamped by the caliper stays very hot. But if you bed-in the brakes with this method they seem to be able to better tolerate being clamped down at red lights.

Thanks for the advise guys.

Quick question before I try replacing the rotors. Are the 1990 rotors as hard to replace as the 1992? I was never able to get them off of my 92.

Yes they have the hub over rotor set up just like the 92.....sorry.

PIA but it can be done. Many options on "how to", I hear there is one of those "eric the car guy" videos somewhere.

HI, I’m just going to be honest, if you haven’t fixed this already, I hope this helps. It sounds as if you have a misfire. I would try to change the spark plugs or the cooling packs. That should solve your problem

This is an almost 10 year old thread, so I'm assuming the original poster resolved the problem.