1979 Ford Bronco Brake Lights Dim

1979 FORD BRONCO
Avatar
NIGHTRIDER2108
  • MEMBER
  • 3 POSTS
hello i live in south ga and recently purchased a 1979 bronco 351m engine c6 auto transmission and i currently have two problems 1 the oil pressure cold runs about 65 lbs after the temp gets to normal 180 degrees at idle it runs approx 5 lbs and going down the road approx 25 lbs of oil pressure. is this normal for a 351m? the next problem is brake lights , actually everything works headlights,taillights, blinkers front and rear, and brake lights work until i turn on the headlights then when i press the brake pedal the brake lights dont brighten up to where you can tell when they come on. whoever had this truck had ran a wire from the brake switch behind the brake pedal to the rear of the truck and its hooked into the brown wire thats for the running lights is this right or wrong? any help would be greatly appreciated.
Mar 26, 2006 at 11:38 AM
Advertisement
Avatar
LOVESCARS
  • ✓Experienced Mechanic
  • 359 POSTS
compare the wires from side to side. Obviously if they ran a jumper wire they had problems somewhere and that somewhere is what you need to idenitfy.
How many bulbs do you have and is the lighting 2 or three phase? I suspect with a 79 the wiring is 2 phase. It sounds like you have not tapped the correct wire normally the socket goes bad or someone puts the wrong bulb in.

The 302 are norious for low oil pressure it could be the oil pressure sending unit though.

The crank and beraings are usually the first things to go. If you decide to do the crank make sure the reman kit you buy has a 10-10 crank these have the least damage and are more reliable.
Mar 26, 2006 at 12:00 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.

Suggested Repair

Compare the rear lighting wires side to side and find the fault that led to the jumper from the brake switch to the brown running-light wire; that tap is likely the wrong circuit. Check for a bad socket or incorrect bulb on a two-filament system. For the hot oil-pressure drop, test the sending unit; if pressure is truly low, crank and bearings are the usual wear points, and a crank replacement should use a 10-10 kit.

Conversation Summary

The owner of a 1979 Ford Bronco with a 351M and C6 reports about 65 psi oil pressure cold, about 5 psi at hot idle, and about 25 psi while driving, and asks if that is normal. Lights and signals work, but the brake lights do not brighten enough to notice once the headlights are on. A previous owner ran a wire from the brake-pedal switch into the brown rear running-light wire. The expert advises comparing wiring side to side, identifying why the jumper was added, and checking for the wrong wire, a bad socket, or the wrong bulb. For oil pressure, the expert suggests the sending unit or worn crank and bearings, and a 10-10 crank if the crank is replaced.

Related Repair Questions

Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle